MIN CI 30 Pcs Strong Round Cup Mgangts wit Hole Heavy Duty, Powerful Rare Earth Neodymium Metal Magnet with Screw for Wall Mounting Industrial, Small Magnets Hole in Center 0.78" D x 0.12" H

They are very strong but a little brittle, they do break a little too easy if you are not careful while mounting them for use.

Lo mas sobresaliente es su fuerza y puedes fijarlo sin pegamentos

There is a reason for the rubber washers between each magnet when the arrive! If you allow them to snap together (which is difficult) they will chip, crack and become unusable. If you over torque the installation screw, the will literally shatter apart. As a result, 4 or 5 were wasted.

These are nice powerful little magnets if used correctly. I used some of mine on the bottom of metal cabinet doors without the screw and they work well. I don't need the screw because they normally stick to the bottom cabinet ledge and holds the door when it shuts.The down side ... they will easily break if too much pressure is applied to the screws that come with the mags. Also, I have no explanation for this, not having a PHD in magnetics, but I haven't had any luck with any application if I use the screw to hold the mag(s). I was simply going to use a couple to hold a light weight screen door closed. I could not get them to work even close to the normal magnetic pull without the screw ... weird. No, I didn't have the polarity messed up.

Be careful when installing. Work as expected but they are brittle to better to hand tighten screws. They will “snap” under to much pressure.

Was specifically looking for 18mm by 3mm as one of the magnets i have in the vent mounting kit broke apart. They look very close, but are in fact 2mm thick and way weaker that the 3mm's i had. Will use those instead of the ones i had with the kit, but if you are looking for the exact size - be aware as these are actually 17mmx2mm

these were the only 3/4" magnets that were a full 1/8" thick, and drilled, that I could find. Very nice.

The magnets are strong and do the job. And they have a beveled hole in the middle!