1.It's a solid magnet tray set with powerful magnetism. The magnets are definitely strong enough to keep everything in place, all the items stick really well even if the magnetic tray is knocked over!
 
2.There is a thick raised rubber disk on the bottom of the magnetic tray, giving it stability so it doesn't slide easily and it won't scratch up whatever surface they are stuck to. 
 
3.3 different size magnet trays, the large magnet trays are big enough to hold plenty of nuts and bolts and the small ones are handy for keeping screws and smaller fasteners organized.