Review on 50Pcs Strong Neodymium Magnets With Hole & Mounting Screws - Heavy Duty Rare Earth Disc Countersunk For Locker, Tool Storage & Crafts by Russ Conrad

I didn't see any mention of how fragile these are in other reviews and thought it would be important to know. the plastic discs that separate them are not just to make them easier to pull apart from one another (which it does), but to keep them from slamming into each other and shattering. If you get one magnet to close to another without the plastic disk between them, they will slam together so fast and hard that one or both will crack. If they pull any other ferrous object within distance to them, that can also crack them. I broke three within a few hours.On the plus side, they are SUPER strong. WOW. They will NOT hold up to repeated impacts, even if you're careful.