The Onyx 1/2" Nano Max Impact Wrench, No. 1823, from Astro Pneumatic Tool Company, offers 625 ft-lbs of max torque and 500 ft-lbs of working torque in three forward and three reverse settings. The lightweight, 4-lb Nano Max was designed with an innovative twin hammer mechanism and short profile of just 4.9". Other features include: 8,500 rpm free speed, 90 PSI, 9.1 cfm and 1/4" air inlet. It is ideal for use in restricted spaces such as engine, transmission and suspension work.