Aluminum oxide grainGeneral purpose, long lifeEasy disc changes by twisting to unlock backing pad, Triple lamination construction for severe duty applications where traditional discs frayQuick change backings make for fast, easy disc changes and less downtimeUniversal backings fit most major backing pad brands on the market2-ply construction is rugged enough for contoured surfaces or flat surfacesSee Accessories for Laminated Disc Backing Pads