... as well, and our dominant products are chisel bits, cross bits, buttons bits, DTH bits with high, medium and low air pressure, ... Bits / Cross Bits / Button Bits Diameter---28mm,30mm 32mm,34mm,36mm,40mm,42mm,44mmThread Drill Bits---Diameter: 51mm to 127mmThread Type---R22,R25,R28, ... .Thread Rod---R25,R28,R32,R38,T38,T45,T51. Integral Drill Rod---H19/H22, Diameter---20mm - 42mm. T51 Thread button bits