Feature aluminum oxide grit resin-bonded to thin, flexible paper backing. Long lasting and water resistant. Used for smoothing and polishing non-ferrous and precious metals. Have 1/16" pinhole centers and can be used with miniature mandrels with 1/16" screws (see related products below). All are 1 1/2" in dia. and are available in 5 grits: 320 grit is the finest. Boxes of 100 discs.