Remind: The 5/8-11 Female Thread Arbor velcro backer/pad holder are with water feed hole, can be used for wet polishing. Important Remind: Rubber Pad holder’s max capacity is 5000 RPM. Please do not use it with high speed grinder or polisher. 48 Pieces of 4 (3.2mm Thickness) Diamond wet dry (wet use recommended) Polishing Pad for granite marble concrete. And 2 Pieces of 4 Diamond Glaze Buffer (they bring mirror like polished result to natural granite marble). And 1 Piece of 4 Backer. (5/8-11 female thread arbor). The 48 Pads are. 10 X Grit 50 100. 8 X Grit 200 400. 4 X Grit 800 1500 3000. Remind: velcro backer’s max capacity is 5000RPM, please don’t use it with high speed polisher/grinder. 3.2mm thickness. Recommend 3500 – 5000 rpm (grinder or polisher speed MUST be lower than 5000 RPM). Wet or dry use (wet use recommended).