... standard hex, Bit diameters include 20-42mm.2. Tapered drilling tools (Tapered Drill Steel)Including:Drill rods with Shank H22x108mm,( ... R32, T38, T45,T51, bit diameter: 45mm-127mm);Couplings sleeves-manufactured with a middle stop to prevent walking ... along the thread. Include couplings sleeve(threaded R22,R25,R28,R32,R38,T38,T45 ... button bits and X type bits etc)v tapered rod