5" x 8 hole industrial quality Starcke German sanding discs are made with Aluminum Oxide grain containing a non-loading stearate to reduce clogging. Grits 80-120 are made on durable "D" weight paper. Grits 150-220 are made on flexible "C" weight paper. Ideal for finish sanding on wood, paint, metal, plastic, and solid surface. To use, attach disc to a hook and loop back up pad on an orbital or DA disc sander. 50 pack of discs with 10 each of grits 80, 100, 120, 150 and 220.