10x3mm 100 Pcs Strong Small Neodymium Magnets, Round Rare Earth Magnets Heavy Duty, for Whiteboard, Decorative Neodymium Magnet

I have worked with quite a few ultra-powerful neodymium magnets in the past 3 years, some of which are outright dangerous if handled recklessly, such as strong enough to crush fingers that get in the way, or outright lift refrigerators and small steel engine blocks. This is not one of those kind of magnets, but I still treat all neodymium permanent magnets with respect for safety.This was the perfect size to replace the anemic weak magnet in the antenna for a cellular network access "fail-over" device, so it would stay put on a vehicle or in a portable application in high winds.The original antenna underwent "sudden violent separation" from a car roof, followed by high velocity contact with the highway surface and dragging by its attached coaxial cable, accompanied by multiple secondary impacts with pavement and the side of the car until the driver was able to come to a stop after about 400 feet. Pieces of debris from the antenna base were recovered from the highway, bagged, and taken home to see if there was any hope of repair; not due to the cost - only a $25 antenna - but the 6 to 8 weeks of supply chain delays to acquire a replacement.Following examination of the debris, it was quickly determined that the tiny magnet used in the base during manufacture was woefully inadequate to hold it to the roof of a vehicle at highway speeds.A small mold was made to replicate the shape of the plastic base, the recovered fragments were placed approximately where they would have been before the accident, the metal parts were verified to still have electrical and RF integrity, and a small amount of resin was poured to reconstruct the base.The steel cup in which the original magnet had been placed, was measured for inside bottom diameter, as was its depth with a machinist's gauge. With sufficient cup clearance calculated to maximize magnetic field strength out of the bottom, these magnets were selected and ordered as the best fit and likelihood of sufficient strength to upgrade the base holding force to an acceptable performance level in the field.While the magnets were en route, the antenna system was tested with a rather expensive microwave antenna and feedline analyzer, and determined to be still functional within the cellular 4G spectrum.The empty cup was filled with JB Weld epoxy (which although it contains steel powder and is slightly magnetic, does not divert more than a few percent of magnetic flux). This was used to "pot" the magnet so when removing the modified rebuilt assembly from a car roof, it will stay firmly attached to the antenna and not the car.24 hours later once the epoxy had fully cured, the repaired unit was placed on the car roof, with a camera anchored nearby to observe it. The antenna analyzer was connected to the coax, and set up to monitor impedance and reflected energy in the center of the 4G cellular spectrum, and the unit was taken on a test drive.The first leg consisted of about 2 miles of incredibly rough dirt road, which subjected the unit to extreme vibration, which should induce microscopic very fast separation and gap closure over millisecond intervals, which can cause data errors and "chopping" of voice over IP. The magnet was strong enough no significant signal degradation was observed.The second leg was about 4 miles of secondary road at between 35 and 50 mph. The final leg was 10 miles out and 10 miles back of highway between 75 and 80 mph to observe aerodynamic behavior and the magnet's ability to overcome these forces.The magnet passed with flying colors.Most people won't use them for this, but it worked well. I'm going to put another one in a TV remote so it stays put on a steel cabinet when not in use, and the cats can't hide it under furniture.

If you want a strong yet small magnet, this will work. A challenge I faced was that the magnets are very polished on both sides, making it tough to get adhesives to stick. I would guess roughing one side up a bit with sandpaper would help adhesive stick better. Overall, these things are great for their size.

I am a bit of a magnet geek - there are so many possible applications. I really like that they are very slim and yet so strong. I have used these for a variety of purposes such as sealing blackout curtains to my window frame so the sun can't shine through the gap. I also have a bunch of these holding pictures to my refrigerator. The magnets are strong enough to adhere to an iron surface through thick felt or other fabrics. The shiny chrome finish has shown no evidence of cracking, scratching, or rusting after over a year of use.

The magnets are very strong in terms of magnetic field strength. However, these are not a solid piece iron. The chip and break very easily. I bought these for a project with my physics class. After the first day, about 10 got completely destroyed.

I loved that I could make a pair of magnetic earrings with this. I can put the magnets on my ears without it being too weak or too strong. Earrings weren’t even the reason I bought these but it’s great that I can use them for that reason. I love this product and I’m definitely coming back for more.

Put these on my gen8 and they work great! While I was installing, a magnet slipped out of my fingers and snapped into another one and broke, totally my fault, these are by nature a little brittle, but VERY strong! I used 16 3/4 inch magnets. Just make sure you match the polarity up, scuff the surface and use good epoxy.

These look good and are consistently sized (some are a little thicker than others but not by much). They stick to each other VERY well. But, they don't stick to metal as well as I hoped. I attached one to a 1.6 oz flashlight and it stayed on a vertical steel surface (file cabinet, shelf support, refrigerator), but could easily be pulled away or slid. I attached one to a 5.5 oz flashlight and it slid down. I used one to hold paper to the refrigerator - it held 1-3 pieces well. But, when I pulled the paper, it easily popped off the magnet letting it (the magnet) fall to the ground - a stronger magnet might allow that paper to be pulled out, but the magnet would (usually) stay stuck. I probably wouldn't use it around kids as it's too easy to pop it of a metal surface. And small magnets and kids are a bad mix anyway...

No frills, no thrills. Just basic rare earth magnets at a good price.