Once the correct torque has been reached, the shaft will flex in sync with the lows of the impact gun and bleed-off torque. 4 Pc - 1/2" Drive Torque Extension Bars: 80, 90, 100, 110 (FT/LB). 4 Pc - 1/2" Drive Flip Impact Sockets: 17x19mm, 21x22mm, 3/4" x 13/16", 7/8" x 15/16".