... as well, and our dominant products are chisel bits, cross bits, buttons bits, DTH bits with high, medium and low air pressure, ... reliability of the products. Tapered Drill BitType --Chisel Bits / Cross Bits / Button Bits Diameter---28mm,30mm 32mm,34mm,36mm,40mm,42mm,44mm ... Thread Drill Bits---Diameter: 51mm to 127mmThread Type---R22, ...