Diamond Polishing Pads 5 inch Wet/Dry 20 Piece Set Granite Stone Concrete Marble 19 Pcs of 5" Diamond POlishing Pad for concrete stone and 1 backer. 19 Pads are: 3 X Grit 50 100 200 400 800, 2 X Grit 1500, 1 X Grit 3000 buff. 1 Pcs Rubber Backer (5/8" Thread arbor). Remind: Rubber Backer's max capacity is 5000RPM. Please don't use it with high speed grinder.