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