Used in the extension rod connection, its function is to transmit the impact energy of the drill piston, as well as the rotational torque, to the drill string without loss. It must withstand and transmit up to 6300 piston strokes continuously, with high strength and reliability. For example: R25 coupling, R25/R32 coupling, R28/T38 coupling, R32 coupling, T38 coupling, etc.

(1) Size: R25, R28, R32, R35, R38, T38, T45, T51, R25-R28, R22-R25, R25-R32, R32-R38, R32-T38.

(2) Length: 140 mm-235 mm