Provides flexibility and conformability to allow for sanding by hand in areas inaccessible to machine sanding. They feature aluminum oxide mineral coating on a foam pad with a waterproof bonding system. Can be used either wet or dry when sanding on wood, fiberglass/gelcoat, marine paints, metals and plastic. Description Fine Grade 320-400 Size 4-1/2" x 5-1/2" Box 20