Note : Credits for the FAQ section below to K&J Magnetics, Inc

After perusing the frequently asked questions to satisfy some of your common queries, if you are ready to buy some raw magnet material of your desired shape, please click here.

On Magnets in General
On Neo or Neodymium Magnets
On Handling Magnets
On Coatings/Adhesives/Plating
On Special Magnets
Special Uses/Applications   



1) How can I identify the poles of the magnets?
2) Is one pole stronger than the other?
3) Which is the strongest type of magnet?
4) What does "Magnetized thru thickness" mean?
5) What materials do magnets attract?
6) What materials can I use to block/shield magnetic fields?
7) Can you supply monopole magnets?
8) Can you supply a disc/cylinder/ring/sphere magnet with one pole on the outside and one on the inside?
9) Does stacking magnets together make them stronger?
10) How is the pull force of each magnet determined?
11) I am using another online magnet pull force calculator. Why is the pull force value from the calculator different from Lifton Magnets' pull force calculator?
12) Will a magnet with a 20 lb pull force lift a 20 lb object?
13) Can you supply BH Curves, or Demagnetization Curves for your magnets?
14) What does a magnetic field look like?
15) How is the strength of a magnet measured?
16) What is the relationship between Flux Density and Pull Force of magnets? How can 2 magnets of different sizes have the same flux density and yet exhibit vastly different pull forces?


1) How can I identify the poles of the magnets?

Answer:
There are several simple methods that can be used to identify the (Scientific) North and South poles of neodymium magnets.
1)The easiest way is to use another magnet that is already marked. The North pole of the marked magnet will be attracted to the South pole of the unmarked magnet.
2)If you take an even number of magnets and pinch a string in the middle of the stack and dangle the magnets so they can freely rotate on the string, the North pole of the magnets will eventually settle pointing North. This actually contradicts the "opposites attract" rule of magnetism, but the naming convention of the poles is a carry over from the old days when the poles were called the "North-seeking" and "South-seeking" poles.   These were shortened over time to the "North" and "South" poles that we know them as.
3)If you have a compass handy, the end of the needle that normally points North will be attracted to the North pole of the neodymium magnet.
4)Use Pole Identifier Devices.
(Please note: In some magnetic therapy applications, the definitions of the poles are reversed from the scientific definition described above. Please be sure to confirm the proper definition of the poles prior to using magnets for medical purposes)

2) Is one pole stronger than the other?

Answer:
No, both poles are equally strong.

3) Which is the strongest type of magnet?

Answer:
Neodymium (more precisely Neodymium-Iron-Boron) magnets are the strongest permanent magnets in the world.

4)What does "Magnetized thru thickness" mean?

Answer:
We use the description "Magnetized thru thickness" to identify the locations of the poles on our block magnets. The thickness is always the last dimension listed for block magnets. If you take one of our block magnets and place it on a flat surface with the thickness dimension as the vertical dimension, the poles will be on the top and bottom of the magnet as it sits.For example: On one of our blocks of 1" x 1/2" x 1/8" thick (25.4 x 12.7 x 3.17mm). If you place one of the blocks so it is on a flat surface with 1/8" (3.17mm) as the vertical dimension, the poles will be on the top and bottom as the magnet sits. This means the poles are located in the middle of the 1" x 1/2" sides (25.4 x 12.7mm).

5) What materials do magnets attract?

Answer:
Ferromagnetic materials are strongly attracted by a magnetic force.   The elements iron (Fe), nickel (Ni), and cobalt (Co) are the most commonly available elements. Steel is ferromagnetic because it is an alloy of iron and other metals.

6) What materials can I use to block/shield magnetic fields?

Answer: Magnetic fields cannot be blocked, only redirected. The only materials that will redirect magnetic fields are materials that are ferromagnetic (attracted to magnets), such as iron, steel (which contains iron), cobalt, and nickel. The degree of redirection is proportional to the permeability of the material. The most efficient shielding material is the 80 Nickel family, followed by the 50 Nickel family.

7) Can you supply monopole magnets?

Answer: No, we don't, nor can anyone else, becuase they don't exist. All magnets must have at least two poles.

8) Can you supply a disc/cylinder/ring/sphere magnet with one pole on the outside and one on the inside?
Answer: Disc, cylinder, and sphere shapes definitely cannot be manufactured this way.   Rings magnetized this way are referred to as "radially magnetized", but it is not currently possible to manufacture neodymium ring magnets this way.   We are working on it, however.

9) Does stacking magnets together make them stronger?


Answer:
Yes, two or more magnets stacked together will behave exactly like a single magnet of the combined size. For example, if you stacked two of our 1/2" x 1/8" (12.7 x 3.17mm) disc magnets to form a 1/2" x 1/4" (12.7 x 6.35mm) combined size, the two magnets would have the same strength and behave identically to the discs which are 1/2" diameter x 1/4" thick (12.7 x 6.35mm).

10) How is the pull force of each magnet determined?

Answer:
All of the pull force values we specify have been tested in our laboratory. We test these magnets in two different configurations. Case 1 is the maximum pull force generated between a single magnet and a thick, ground, flat steel plate. Case 2 is the maximum pull force generated with a single magnet sandwiched between two thick, ground, flat steel plates. Case 3 is the maximum pull force generated on a magnet attracted to another magnet of the same type. The values are an average value for five samples of each magnet. A digital force gauge records the tensile force on the magnet. The plates are pulled apart until the magnet disconnects from one of the plates. The peak value is recorded as the "pull force". If using steel that is thinner, coated, or has an uneven or rusty surface, the effective pull force may be different than recorded in our lab.

11) I am using another online magnet pull force calculator. Why is the pull force value from the calculator different from Lifton Magnets' pull force calculator?

Answer:
Most other online calculators are based on theoretical formulas, which are notoriously inaccurate, especially for very large or very small sizes. Our fanatical engineers have worked long and hard in the laboratory developing our calculation method that are VERY accurate based on thousands of test cases. ten samples of each magnet. A digital force gauge records the tensile force on the magnet. The plates are pulled apart until the magnet disconnects from one of the plates. The peak value is recorded as the "pull force". If using steel that is thinner, coated, or has an uneven or rusty surface, the effective pull force may be different than recorded in our lab.

12) Will a magnet with a 20 lb pull force lift a 20 lb object?

Answer:
Because pull force values are tested under laboratory conditions, you probably won't achieve the same holding force under real world conditions. The effective pull force is reduced by uneven contact with the metal surface, pulling in a direction that is not perpendicular to the steel, attaching to metal that is thinner than ideal, surface coatings, and other factors.

13) Can you supply BH Curves, or Demagnetization Curves for your magnets?

Answer: Yes, we supply Demagnetization Curves for Neodymium magnet upon customers' request.

14) What does a magnetic field look like?

Answer: The traditional way of visualizing magnetic fields is to place a magnet near a surface covered with iron filings. If you already have some of our magnets, this is a good experiment to conduct!

15) How is the strength of a magnet measured?

Answer: Gaussmeters are used to measure the magnetic field density at the surface of the magnet. This is referred to as the surface field and is measured in Gauss (or Tesla).   Pull Force Testers are used to test the holding force of a magnet that is in contact with a flat steel plate. Pull forces are measured in pounds (or kilograms).

16) What is the relationship between Flux Density and Pull Force of magnets? How can 2 magnets of different sizes have the same flux densities and yet exhibit vastly different pull forces?

Answer: There is a direct relationship between the Flux Density of the magnetic material and the Pull Force per square inch (or 'cm' or 'mm') of the magnets that are used.  The Pull Force number takes into account the size and shape of the magnet along with the flux rating of the material from which it is made. 

The formula for finding the Pull Force of a cube or bar magnet is as follows:

Pull Force = 0.576 x Br² x (Th) x √‾A where

Br = Remanence or Flux Rating in KiloGauss.

Th = Thickness of Magnetized Surfaces in inches

A = Surface Area (L x W) in inches

A Grade 8 Ceramic Magnet (3,900 Gauss material) that is 4 Inch Long, 1 Inch Wide, and 1 Inch Thick will have a Pull Force as follows:

Pull Force = 0.576 x Br² x (Th) x √‾A

              = 0.576 x (3.9)² x (1) x √‾4

              = 0.576 x 15.21 x 1 x 2

Pull Force = 17.52 Pounds

That translates into 4.38 Pounds of Pull Force per Square Inch (17.52 lb. ÷ 4")

 

A N42 Grade Neodymium Magnet that is 2" Long, 1 Inch Wide and .5 Inches Thick will have a Pull Force as follows:

Pull Force = 0.576 x Br² x (Th) x √‾A

              = 0.576 x (13.2)² x (.5) x √‾2

              = 0.576 x 174.24 x .5 x 1.414

Pull Force = 70.96 Pounds

That translates into 35.48 Pounds of Pull Force per Square Inch (70.96 lb. ÷ 2").

 

So this Neodymium magnet that is half as long and half as thick as the large Ceramic Magnet has a Pull Force per square inch that is 8.1 times higher than the larger Ceramic magnet.   


On Neo or Neodymium Magnets


1) What are neodymium magnets? Are they the same as "rare earth" magnets?
2) What are neodymium magnets made from and how are they made?
3) Can I solder or weld to neodymium magnets?
4) What is the gauss rating of your magnets?
5) Do neodymium magnets require a keeper?
6) Will my neodymium magnets lose strength over time?
7) Will neodymium magnets lose strength if they are held in repelling or attracting positions for a long time?
8) What are neodymium magnets used for?
9) How is neodymium pronounced?
10) Are your Neodymium Rare Earth Magnets RoHS compliant?
11) Can I make a magnet that I already have any stronger?
12) I need a magnet the size of a penny/nickel/dime/quarter.   What size do I need?
13) What is the difference between the maximum operating temperature and the Curie temperature of the magnets?
14) Can I cut, drill, or machine neodymium magnets?
15) What does the " N rating ", or grade, of the neodymium magnets mean?
16) How strong of a magnetic field is necessary to magnetize a neodymium magnet?
17) Do I have to worry about temperature with neodymium magnets?


1) What are neodymium magnets? Are they the same as "rare earth" magnets?

Answer:
Neodymium magnets are a member of the rare earth magnet family. They are called "rare earth" because neodymium is a member of the "rare earth" elements on the periodic table. Neodymium magnets are the strongest of the rare earth magnets and are the strongest permanent magnets in the world.

2) What are neodymium magnets made from and how are they made?

Answer:
Neodymium magnets are actually composed of neodymium, iron and boron (they are also referred to as NIB or NdFeB magnets).  The powdered mixture is pressed under great pressure into molds.  The material is then sintered (heated under a vacuum), cooled, and then ground or sliced into the desired shape. Coatings are then applied if required. Finally, the blank magnets are magnetized by exposing them to a very powerful magnetic field in excess of 30 KOe.

3) Can I solder or weld to neodymium magnets?

Answer:
You definitely cannot solder or weld to neodymium magnets. The heat will demagnetize the magnet and could cause it to catch fire posing a safety risk.

4) What is the gauss rating of your magnets?

Answer:
This depends on the context it is used. Most magnetic therapy people like to present the largest number possible, so they often use the Residual Flux Density (BrMax) of the material, which really doesn't specify much about the actual magnet. This value is
essentially the magnetic field density inside the magnet material.   Since you will never be inside the magnet, or using the field inside the magnet, this value doesn't really have any practical use.   The surface field of a magnet is a much more accurate specification for a magnet.   The surface field is exactly what it sounds like. It is the magnetic field density at the surface of the magnet as measured by a Gaussmeter. This value is tested and specified for each of our stock magnets.

5) Do neodymium magnets require a keeper?

Answer:
No, neodymium magnets do not require a keeper for storage like Alnico magnets

6) Will my neodymium magnets lose strength over time?

Answer:
Very little. Neodymium magnets are the strongest and most permanent magnets known to man. If they are not overheated or physically damaged, neodymium magnets will lose less than 1% of their strength over 10 years - not enough for you to notice unless you have very sensitive measuring equipment. They won't even lose their strength if they are held in repelling or attracting positions with other magnets over long periods of time.

7) Will neodymium magnets lose strength if they are held in repelling or attracting positions for a long time?

Answer:
In most applications, the answer is simply "no". If the magnets will be exposed to higher temperatures while in repelling applications, the answer is "possibly". The exact answer is a bit too complicated for a FAQ answer, and requires specifics about the application.

8) What are neodymium magnets used for?
Answer: Just about anything you can imagine!

9) How is neodymium pronounced?

Answer:
From a dictionary : [ne"odim'eum]
The only real trick to pronouncing it correctly is to treat the 'y' as an 'i'.   It is pronounced as if it were spelled "neodimium".

10) Are your Neodymium Rare Earth Magnets RoHS compliant?

Answer:
Yes, our magnets are fully RoHS compliant, meeting the European Parliament Directive entitled "Restrictions on the use Of Hazardous Substances" (RoHS). This Directive prohibits the use of the following elements in electrical/electronic equipment sold after 7/1/2006: cadmium (Cd), lead (Pb), mercury (Hg), hexavalent chromium (Cr(VI)), polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs).

11) Can I make a magnet that I already have any stronger?

Answer:
No, once a magnet is fully magnetized (saturated), it cannot be made any stronger.

12) I need a magnet the size of a penny/nickel/dime/quarter.   What size do I need?

Answer:
Here are the dimensions of these coins along with the closest matching magnet that we currently stock:
US Penny = 0.75" dia. x 0.061" (19.05 x 1.55mm) disc magnet
US Nickel = 0.84" dia. x 0.077" (2.13 x 0.19mm) disc magnet
US Dime = 0.71" dia. x 0.053" (1.80 x 0.13mm) disc magnet
US Quarter = 0.95" dia. x 0.069" (2.41 x 0.17mm) disc magnet
US Half Dollar = 1.21" dia. x 0.085" (3.07 x 0.21mm) disc magnet

13) What is the difference between the maximum operating temperature and the Curie temperature of the magnets?

Answer:
The maximum operating temperature is the maximum temperature the magnet may be continuously subjected to with no significant loss of magnetic strength. This is 176ºF (80ºC) for standard grades of neodymium magnets. The Curie Temperature is the temperature at which the magnet will become completely demagnetized. This is 590ºF (310ºC) for standard grades of neodymium magnets. Higher temperature grades have higher maximum operating temperatures and higher Curie Temperatures. At temperatures between these two points, a magnet will permanently lose a portion of its magnetic strength. The loss will be greater the closer to the Curie Temperature it is heated.

14) Can I cut, drill, or machine neodymium magnets?

Answer:
The Neodymium Iron Boron material is very hard and brittle, so machining is difficult at best. The hardness of the material is RC46 on the Rockwell "C" scale, which is harder than commercially available drills and tooling, so these tools will heat up and become damaged if used on NdFeB material. Diamond tooling, EDM (Electrostatic Discharge Machines), and abrasives are the preferred methods for shaping neodymium magnet material. Machining of neodymium magnets should only be done by experienced machinists familiar with the risk and safety issues involved. The heat generated during machining can demagnetize the magnet and could cause it to catch fire posing a safety risk. The dry powder produced while machining is also very flammable and great care must be taken to avoid combustion of this material.

15) What does the " N rating ", or grade, of the neodymium magnets mean?

Answer:
The grade, or "N rating" of the magnet refers to the Maximum Energy Product of the material that the magnet is made from.  It refers to the maximum strength that the material can be magnetized to.   The grade of neodymium magnets is generally measured in units millions of Gauss Oersted (MGOe).   A magnet of grade N42 has a Maximum Energy Product of 42 MGOe. Generally speaking, the higher the grade, the stronger the magnet.

16) How strong of a magnetic field is necessary to magnetize a neodymium magnet?

Answer:
As a general rule of thumb, a peak field of between 2 and 2.5 times the intrinsic coercivity is required to fully saturate a magnet. For standard neodymium magnets, the field required is minimum of 24 KOe, but 30 KOe is usually the minimum used.

17) Do I have to worry about temperature with neodymium magnets?

Answer:
Yes.   Neodymium Iron Boron magnets are sensitive to heat.   If a magnet heated above its maximum operating temperature (176°F (80°C) for standard N grades) the magnet will permanently lose a fraction of its magnetic strength.   If they are heated above their Curie temperature (590°F (310°C) for standard N grades), they will lose all of their magnetic properties.   Different grades of neodymium possess different maximum operating and Curie temperatures.

On Handling Magnets


1) How can I separate strong magnets?
2) I have metal dust all over my magnets. How can I remove it?
3) Are there any regulations for shipping magnets?

1) How can I separate strong magnets?

Answer:
Small and medium-sized magnets can usually be separated by hand by sliding the end magnet off of the stack. Medium-large magnets can often be separated by using the edge of a table or countertop. Place the magnets a table top with one of the magnets hanging over the edge. Then, using your body weight, hold the magnet(s) on the table and push down on the magnet hanging over the edge. With a little work and practice, you should be able to slide the magnets apart. Just be careful that they don't snap back together once they become separated.   For very large magnets (generally 2" and larger), we use a specially made magnet separating tool.

2) I have metal dust all over my magnets. How can I remove it?

Answer:
Using adhesive tape to capture the metal dust is the best way to clean magnets.

3) Are there any regulations for shipping magnets?

Answer:
According to the United States Department of Transportation and the Office of Hazardous Materials Safety, the limit for shipping magnets by air is a magnetic field strength of 0.00525 Gauss measured at 15 feet (4.5 meters) from any point on the outside of the package. There are no restrictions on the shipping of magnetized materials by ground. When in doubt, ship magnets by ground transportation.


1) Why are most neodymium magnets plated or coated?
2) Can I paint over the nickel plating?
3) What is the difference between the different platings and coatings?
4) What is the thickness of the nickel (Ni-Cu-Ni) plating?
5) Do you stock any unplated magnets?
6) What is the best adhesive to use with your magnets?
7) I noticed that the plastic- and rubber-coated magnets have a lower pull force than nickel-plated magnets of the same size. Does the plastic/rubber weaken the magnet?
8)  How can I protect my magnets from damage due to impact?


1) Why are most neodymium magnets plated or coated?

Answer: Neodymium magnets are composed mainly of Neodymium, Iron, and Boron. If neodymium magnets are not plated, the iron in the material will oxidize very easily if exposed to moisture. Even normal humidity will rust the iron over time. To protect the iron from exposure to moisture, most neodymium magnets are plated or coated.

2) Can I paint over the nickel plating?

Answer: Yes, you can use any paint formulated for use on metal surfaces. Spray-on paint seems to work best.

3) What is the difference between the different platings and coatings?

Answer: The coatings do  not affect the magnetic  strength or performance of the magnet.   The preferred coating is dictated by preference or by the magnets intended application.   Nickel is the most common choice for plating neodymium magnets, and is actually a triple plating of nickel-copper-nickel.   It has a shiny silver finish and has good resistance to corrosion.   Black nickel has a shiny, black/charcoal appearance and is slightly more corrosion resistant than regular nickel.   It is also a triple plating of  nickel-copper-black  nickel.   Zinc  has  a  dull  gray/bluish  finish,  that  is  more  susceptible  to  corrosion  than nickel.   Zinc can leave a black residue on hands and other items.   Epoxy is basically a plastic coating that is virtually 100% corrosion resistant as long as the coating is intact.   From our experience, it is the least durable of the common coatings.   Gold plating is applied over the top of nickel plating, so gold plated magnets have the same characteristics as nickel plated ones, but with a gold finish.

4) What is the thickness of the nickel (Ni-Cu-Ni) plating?

Answer: The nickel plating is actually triple plating of nickel-copper-nickel. The layers are Ni: 5-6µm, Cu: 7-8µm, Ni: 5-6µm, for a total thickness of 17-20µm.

5) Do you stock any unplated magnets?

Answer:
As mentioned above, the iron in the NdFeB material will oxidize if it is exposed to moisture. For this reason, we do not stock any unplated magnets. We can supply unplated magnets as custom order items.

6) What is the best adhesive to use with your magnets?

Answer: We and several customers have had great success adhering to the nickel-plating using Loctite 39205 with Loctite 7380 activator. A Loctite representative has also recommended Loctite 3032 with Loctite primer 770. For more commonly found adhesives, we have also had good results using "JB Weld" epoxy, "Liquid Nails", "Gorilla Glue", "Cow Glue", "Superglue" which are available in most hardware and home supply stores. It does help to scratch the surface of the plating lightly with sandpaper or other abrasive prior to applying the adhesive.

7) I noticed that the plastic- and rubber-coated magnets have a lower pull force than nickel-plated magnets of the same size. Does the plastic/rubber weaken the magnet?

Answer: These materials don't "weaken" the magnet, but the volume of magnet material is reduced to allow room for the coatings, which reduces the pull force. The layer of plastic or rubber also creates distance between the magnet and metal surface which also reduces the pull force.

8)How can I protect my magnets from damage due to impact?

Answer:
We have found that wrapping magnets with a few layers of electrical tape protects them from most damage caused by collisions with other magnets and hard surfaces.   Another great way to protect your magnets from damage and the elements is to coat them with rubberized coating.

On Special Magnets


1) Can you supply custom/special shapes of neodymium magnets?
2) What are the size limitations on manufacturing neodymium magnets?
3) Can you just put my magnets in a small envelope to save postage?
4) Are there health or safety concerns with neo magnets?
5) What is a safe distance to keep magnets away from pacemakers?
6) Will magnets harm my electronics?
7) How far away from electronics should I keep my magnets?
8) Will using magnets on my refrigerator, stove, oven, or microwave harm the appliance?
9) Will magnets erase my hard drive or harm my computer?
10) I am developing a product using magnets. Do I have to put a safety warning on it about pacemakers/electronics?

1) Can you supply custom/special shapes of neodymium magnets?

Answer:
Yes, we can supply custom magnets.

2) What are the size limitations on manufacturing neodymium magnets?

Answer:
Approx 3" max in magnetized direction Approx 6" max diameter for discs and rings, approx 8" max length and width for blocks, Approx 1/32" minimum on thickness on any magnet Approx 1/16" minimum diameter on outer diameter Approx 1/16" minimum diameter on any hole

3) Can you just put my magnets in a small envelope to save postage?

Answer:
No. If they are being sent by airfreight, all magnets must be shipped in a box in order to comply with United States Department of Transportation, USPS, UPS, and FedEx regulations for the shipment of magnetic materials.

4) Are there health or safety concerns with neo magnets?

Answer:
There are no known health concerns with exposure to permanent magnetic fields. In fact, many people believe that magnets can be used to speed up the healing process. We are not medical professionals, so we cannot offer guidance on health or safety. Please consult a physician for this information. There are several safety concerns when handling strong magnets.

5) What is a safe distance to keep magnets away from pacemakers?

Answer:
We are not medical professionals, so we cannot offer guidance on pacemaker safety. Please consult a physician for this information.

6) Will magnets harm my electronics?

Answer:
Maybe...The strong magnetic fields of these magnets can damage certain magnetic media such     as floppy disks, credit cards, magnetic I.D. cards, cassette tapes, video tapes or other such devices.   They can also damage televisions, VCRs, computer monitors and other CRT displays. Never place neodymium magnets near any of these appliances.   As for other electronics such as cell phones, iPods, flash drives, calculators and similar devices that do not contain magnetic storage media, probably not, but it is best to err on the safe side and try to avoid close contact between neo magnets and electronics.

7) How far away from electronics should I keep my magnets?

Answer:
This depends on a lot of factors, but as a general rule of thumb, we recommend keeping the distance between magnets and electronics 4" + 1" for every 10 lbs of pull force.

8) Will using magnets on my refrigerator, stove, oven, or microwave harm the appliance?

Answer:
No, magnets will not harm any of these appliances.

9) Will magnets erase my hard drive or harm my computer?

Answer:
Not unless you really work at it. While you probably don't want to stick magnets directly to your computer case, having them nearby will not harm your computer. Magnets can damage floppy disks and magnetic tape storage media, so you must keep magnets away from these items. They will not, however, damage any data on your hard drive unless you place a very large and powerful magnet directly on top of the drive.   Every hard drive already contains a powerful neodymium magnet, so one moving around outside the case will not affect the data.

10) I am developing a product using magnets. Do I have to put a safety warning on it about pacemakers/electronics?

Answer:
Again, we are not medical professionals, so we cannot comment on pacemaker issues. As for safety and electronics, it really depends on the application of your product, the size of the magnet(s), how the magnet is used, and where the magnet is located within the product. We recommend providing any warnings that you think may be an issue.


1) Do you have a local distributor near me?
2) Where are you located?

1) Do you have a local distributor near me?


Answer:
We do not have any local distributors of our magnets. All sales are through web-orders, emails, phone and fax etc.

2) Where are you located?

Answer:
Our main office facility and warehouse are currently located in Singapore. You may buy from our massive online collection directly off our website. We also accept walk-in customers or pick-ups at this time.


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