4 Inch Diamond Polishing pads for granite marble concrete glass travertine 16+1 Pieces. 16 Pieces of Pad are: 2 X GRit 15 30 50 100 200 400, 1 X Grit 800 1500 3000 10000. 1 Piece of 4 Inch Velcro Backer / Pad Holder. Pad holders max velocity is 5000 RPM. Please NEVER use it with high speed grinder / polisher. Pads can be wet or dry use, wet use recommended. Electric Drill is NOT using with polishing pads.