Diamond Polishing Pads 4" inch Wet/Dry Set of 9+1 Rubber Backer Pad 3mm Thick Granite Concrete 9 Pcs of 4" Diamond Polishing Pad (3mm Thick) for concrete stone and 1 backer. 9 Pads are: 1 X Grit 30 50 100 200 400 Grit 800 1500 3000 10000Super buff. 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.