2QUOT;X72QUOT; BELT SANDER/GRINDER Rubber Drive Wheel, 4" Knife Making Wheel, 3/4" Bore You are bidding on one New Smooth Rubber Drive Wheel for use with 2" wide grinding belts. This wheel is 100mm(approx 4") x 50mm(approx 115/16") x 32mm(approx 3/4") of solid medium density rubber. This wheel has a 3/4" smooth bore.