Diamond Polishing Pads 5" inch Wet/Dry Set of 52+1 Backer Pad Best Value Granite Concrete 52 Pieces of 5" Diamond Polishing Pad (3mm Thick) for concrete stone and 1 backer. 52 Pads are: 10 X Grit 50, 6 X Grit 100 200 400 800 1500 3000 6000Buff. 1 Pcs Velcro Backer (5/8" Thread arbor). Backer has water feed hole, wet polishing no problem. Velcro Backer's max capacity is 5000RPM. Please don't use it with high speed grinder.