our abrasive sanding blocks are washable, re-usable, and can be used to sand flat or contoured surfaces wet or dry while outlasting the life of conventional sandpapers . Abrasive sanding blocks are used on wood,metal,paint and fiber glass surface. abrasive sanding blocks are packaged 250 pcs/carton bulk. Common grit choices are 60, 80, 100, and 180 a/. O. Special orders with other grits in a/o or s/c are always welcome.