5" No hole blue Kassteel PSA Sticky back 80 grit aluminum Oxide sanding discs are excellent for demanding applications. Industries: woodworking, automotive, metalworking, composites, marine, aerospace & solid surface work. Materials: aluminum, stainless steel, fiberglass, composites, body filler, putty, paint, primer, clear coat, polyurethane, epoxy, softwoods, hardwoods, polyester solid surface & acrylic solid surface.