Ingersoll Rand 231C 1/2-inch Drive Heavy-Duty Air Impact Wrench CLASSIC, RELIABLE DESIGN: The 231C has set the standard for over 30 years, making it one of the most popular impact wrenches in the world. SHEER POWER: Twin-hammer impact mechanism delivers 600 ft-lbs of maximum torque with smooth, balanced blows. LONGER TOOL LIFE: 231C arrives fully lubricated and its pressure-fed lubrication system automatically greases the impact mechanism resulting in a more durable impact wrench mechanism delivers a maximum torque of 600 foot-pounds EASY MAINTENANCE: Ergonomic 2-piece design is easy to operate and maintain Exclusive impact mechanism Pressure-feed lubrication Adjustable power regulator