4-3/4" x 3-3/4" x 1/2" flexible foam sponge that is coated on both sides with Aluminum Oxide abrasive. Ideal for sanding in hard to reach places. Used by professional painters, drywall sanders and furniture refinishers. Can be used on wood, metal and painted surfaces. Great for general polishing in the woodworking, cabinetry and automotive industries. Medium is equivalent to a 120-150 grit in traditional sandpaper. 20 sponges per pack.