JAW GAP SHAFT GROUP FOR KN 41 HBC AND KN 41 HBS TYPE WELDING MACHINES WHICH HAS HYDRO-PNEUMATIC UPSETTING PISTON. 1 GROUP CONSISTS 1 PCS JAW GAP NUT, 1 PCS HP UPSET JAW GAP SHAFT, 1 PCS Q10 STEEL BALL AND WEDGE KEY.