... R22 R25 R28 R32 T38 T45 T51 T60 2)rod type: hex or round(plain) 3)length:280mm-6400mm Extension ... Rock Drilling Tools:Coupling Sleeves, Thread Button Bits, Extension Rod, Shank Adaptors.Extension drill rodD: 32,38,45,51mmL: ... 800-6100mmThread: R32, R38, T38, T45, T51Thread type:Hex25, Hex28, R32, R38, R45, R51, H32, Hex35, T45 ... -H28-R283050R28 MF1220R28 MF3050 Steel extension drill Rod