TileRite dry cut diamond drill bit. Suitable for the drilling of porcelain, granite & travertine tiles. Revolutionary new design that requires no water. Use an electric drill at 2000-3000rpm. Can be used with the tile rite stainless steel universal guide with suction cup. 45mm drill bit: Hole size suitable for 38mm waste pipe (1.5 ins). 25 mm drill bit: Hole size suitable for 22mm copper pipe.