... guarantee the high quality and reliability of the products.Tapered Drill BitType --Chisel Bits / Cross Bits / Button ... 28mm,30mm 32mm,34mm,36mm,40mm,42mm,44mmThread Drill Bits---Diameter: 51mm to 127mmThread Type---R22 ... Suitable for had rock ( more than 2067bar)Drill RodSteel Drill Rod---H19/H22, Length: 0.5M to ... ,R38,T38,T45,T51. Integral Drill Rod---H19/H22, Diameter---20mm - 42mm. tapered drill bit