1.Long-life, 2.High penetrability. 3.Can match many famous drilling machine, such ... ,R28,R32,R38,T38,T45,T51Face Shape---Plate, Concave, Convex.Bit Shank & Coupling sleeve---R22,R25,R28,R32,R38,T38,T45 ... ,T51Down-The-Hole Tools1) DTH BIT---65MM to 254mm.2) DTH Hammer---76MM /90MM /110MM 3) Face ShapeConvex ... Drill Rod---H19/H22, Diameter---20mm - 42mm. rock tapered chisel bit