Made of stainless steel material, strong and durable. PVC bottom prevent from being scratchet Includes Round 3" x 3", 4" x 4"and 6" x 6"trays. Strong magnetic force, suitable for keeping track of small parts and tools. Widely used in automobile repair, machine tool operation, etc. Holds metal parts,For screws, nuts, nails, drill bits, sockets and other metallic objects that should not be lost. Keep small hardware parts visible, handy and secure anywhere. Can be used vertically, upside-down and horizontally. One powerful magnet with rubber cover, prevent sliding and marking.