... of the craftworks and inventions guarantee the high quality and reliability of the products.Tapered Drill BitType --Chisel Bits / Cross Bits / Button ... ---Suitable for medium-hard rock (1033.5bar~2067bar)Plate ---Suitable for had rock ( more than 2067bar)Drill RodSteel Drill Rod---H19/H22, Length ... Rod---R25,R28,R32,R38,T38,T45,T51. Integral Drill Rod---H19/H22, Diameter---20mm - 42mm. rock drill bits