Remind: They are 5/8"-11 Thread. NOT M14 Thread. This package carries (a)-(b): (a) 1 Piece of B20 (3/4" / 20 mm) for 20 mm high / thick stone or travertine or concrete counter top / tile edge router bit to do demi / roundover shape bullnose (with 5/8"-11 Thread arbor). (b) 5 Pieces of 2" / 50mm Wet Polishing Drum for granite marble concrete sink / basin hole / sink cutouts / tight radius (with 5/8"-11 Thread arbor) They are: 1 Piece of Grit 50 200 800 1500 3000. Fits on wet / water-fed polisher, Wet and Dry Use, Wet use recommended. -Vertical oscillation recommended for even wear; -Ideal speed (of polisher / grinder) capacity is 4000 RPM, Not be higher than 5000 RPM.. Wet Diamond Polishing Drum Wheel is designed for wet polishing of sink cutouts or tight radius.