1/2square drive drive. Heavy duty air impact wrench quality heavy duty wrench with powerful torque from the efficient motor. Ruggedly built for reliable use. One hand easy forward & reverse direction change. Variable position power regulator for simple speed & power control. Display carton. specification:. Roller pin. 16mm. 280lb-ft (38.7kg/m). 90psi (6.2bar). 4.0cfm (114l/min). 3/8 i.d. 1/4 bsp. 2.4kg.