Diamond Polishing Pads 4 inch Wet/Dry 15 Piece Set Pad Granite Concrete 4" Diamond Polishing Pad concrete granite 14+1 Pieces 14 Pads are: 3 Pcs X Grit 50 100, 2 Pcs X Grit 200 400, 1 Pcs X Grit 800 1500 3000 Buff 1 Pcs X 4" Rubber Backer/Pad Holder (5/8 Thread) Rubber Backer's max capacity is 5000RPM. Please don't use it with high speed grinder/polisher.