Pad holder’s max velocity / capacity is 5000 RPM. Please do not use it with high speed grinder or polisher. 12 Pieces of 7 / 7 Inch / 180mm Higher Diamond Concentration More Long Lasting Polishing Pad for granite marble concrete. 2 X Grit 50 100 200 400. 1 X Grit 800 1500 3000 10000. And 1 piece of 7 Inch PVC Pad Holder. Its arbor is 5/8-11 Female Thread. Important: grinder or polisher speed must be lower than 5000 RPM when using with pad holder. Recommend 2500 – 5000 rpm (grinder or polisher speed must be lower than 5000 RPM). Wet or dry use (wet use recommended).