7 / 180mm Honeycomb Pattern More Durable Diamond Polishing Pad for concrete granite marble engineer stone. The rubber backer’s arbor is 5/8-11 Female Thread. 33 Pieces of 7″ / 180mm Inch Premium Grade D iamond Polishing Pad for granite concrete marble engineered stone and 2 pieces of 7″ Rubber Backer/Pad Holder (5/8-11 female thread arbor). 7 X Grit 50 100. 6 X Grit 200 400. 2 X Grit 800 1500. 1 X Grit 10000. 2 Pcs of 7″ Rubber Backer (5/8″ female thread arbor). Remind: Please NEVER use high speed grinder polisher with rubber backer (Rubber Backer’s max capacity is 5000RPM). 3.2mm thickness. Recommend 3500 – 5000 rpm. Wet or dry use.