Diamond Wheels 400 Grit 7pc Set This is a new set of 5 diamond coated 400 grit cutting wheels and 2 mandrels These are used for cutting, grinding, cleaning, etc One mandrel has a 1/8" (3 mm) shank and the other has a 3/32" (2.5 mm) shank Each wheel measures approximately 3/4" (19 mm) in diameter