Remind: This cup wheel a Two in One cup wheel. The aluminum base is also a 5/8″-11 Thread 6″ aluminum polishing pad holder / backer (5/8-11 FEMALE thread arbor). (a) The aluminum base. It is also a 5/8″-11 Thread 6″ aluminum polishing pad holder / backer (5/8-11 female thread arbor). (b) The diamond segmented working layer of the grinding cup wheel. (c) 15 Pieces of 6 Diamond (3.2mm Thickness) Polishing Pad for granite marble cncrete glass quartz travertine. 3 X Grit 50 100 200. 2 X Grit 400. 1 X Grit 800 1500 3000 6000. Wet and dry use, wet use recommended.