... got the Certificate of ISO9001 in 1999 Tapered Button bits, Retrac Button Bits, Rock tools, Rock drilling tools, drilling bits, ... , Crossover Coupling, drifting rods, Tapered Rod integral drill steel, Retrac X-type bits, Cross Bits,high pressure drilling tools, DTH ... ( Hex.32mm, 35mm, 38mm; Round 32mm, 38mm, 45mm, 51mm)Retrac Button bits with different Thread different diameters. (51mm, 64mm,70mm ...