Craftsman 19981 3/8" Pistol Grip Impact Wrench for $39.99.  Order online for in-store pickup at Sears to lock in the price and save on shipping.  Otherwise, shipping is free on orders over $49.  Here is a screenshot for reference. It has a through-handle air exhaust with 145 ft/lbs of torque, 3/8" ratchet drive size, and variable trigger speed.