... Drilling tools and Coal Mining Tools. Main products:Tapered button bits (28mm, 30mm 32mm, 34mm, 36mm, 40mm, ... 22mm, 25mm)Integral Drill rods( Chisel Bit integral. Rod 19mm, 22mm; Shank hex. 19mm, 22mm)Thread Button Bits (33mm, 35mm ... 35mm, 38mm; Round 32mm, 38mm, 45mm, 51mm)Retrac Button bits with different Thread different diameters. (51mm, 64mm,70mm ... good, but the price is low. button rock drill bit