3" x No Hole Eclipse Film Hook & Loop 320 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.