11 Pcs of 4" Diamond Polishing Pad (3mm Thick) for concrete stone and 1 backer. * 11 Pads are: 2 X Grit 50 100 200, 1 X Grit 400 800 1500 3000 10000Super buff. * 1 Pcs Velcro 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.