Diamond Polishing Pad 5 inch 8 Pieces Rubber Backer Wet/Dry Granite Concrete 8 Pcs of 5" Diamond Polishing Pad (3mm Thick) for concrete stone and 1 backer. 8 Pads are: 1 X Grit 50 100 200 400 800 1500 3000 10000superbuff. 1 Pcs Rubber Backer (5/8" Thread arbor). Backer has water feed hole, wet polishing no problem. Remind: Velcro Backer's max capacity is 5000RPM. Please don't use it with high speed grinder.