(c) 10 Pieces of 4″ Diamond (3.2mm Thickness) Polishing Pad for granite marble cncrete glass quartz travertine 1 X Grit 15 30 50 100 200 400 800 1500 3000 10000. The aluminum base is also a 5/8″-11 Thread 4″ aluminum polishing pad holder / backer (5/8″-11 thread).