Their arbor of them is 5/8-11 Female Thread. This package carries (a)-(c). (a) 1 Piece of 2 / 50mm Diamond Zero Tolerance Grinding drum wheel (to do sink hole inner coarse grinding, shaping, enlarging). (the arbor is 5/8-11 Female Thread arbor). (b) 1 Piece of 4″ / 100mm Velcro Polishing Pad Holder 5/8″-11 Thread arbor. Velcro pad holder’s max velocity is 5000 RPM. Please do not use it with high speed grinder polisher. And 25 Pieces of 4 / 100mm Diamond Polishing Pad for concrete granite stone. 5 X Grit 50 100. 4 X Grit 200 400. 2 X Grit 800 1500 3000. 1 X Grit 6000. (c) 7 Pieces of 2″ / 50mm Wet Polishing Drum for granite marble concrete sink / basin hole / sink cutouts / tight radius (the arbor of them is 5/8″-11 Female Thread). 1 Piece of Grit 50 100 200 400 800 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. A complete set usually comes with grit 50,100, 200,400, 800, 1500, 3000. Polish from grit 50 to 3000 respectively.