1/2'' square drive. Removes most lug nuts and bolts for overall automotive service, body shop, farm, and light truck work. Patented single hammer impact mechanism provides 275 ft./lb. of working torque. Direction control/variable speed regulator for speed control. Patented balanced ergonomic design for end user comfort. Exhaust diffuser for quiet operation. 1/4'' NPT (screened filter) air inlet keeps dirt and debris from damaging air tool. Requires a 3.0 CFM at 90 P.S.I.