The BOSCH GDS18V-221B25 18V EC Brushless 1/2” Impact Wrench Kit is designed for driving high-torque bolts, nuts, and anchors. BOSCH GDS18V-221B25 18V EC Brushless 1/2” Impact Wrench Kit features Auto Bolt Release, which stops rotation when there is no torque on the tool to prevent accidentally dropping bolts and nuts during removal. BOSCH GDS18V-221B25 18V EC Brushless 1/2” Impact Wrench Kit also has Boschs hammer-and-anvil system, which delivers great impact energy. The efficient EC Brushless motor features a long runtime and delivers up to 221 Ft.-Lbs. of torque, 0-3,400 no-load ipm and 0-2,400 no-load rpm. BOSCH GDS18V-221B25 18V EC Brushless 1/2” Impact Wrench Kit was built with a compact design; it has a 6.4 In. head length and a weight of just 2.77 Lbs. BOSCH GDS18V-221B25 18V EC Brushless 1/2” Impact Wrench Kit includes two next-gen CORE18V 4.0 Ah compact batteries. Each keeps the power and runtime, while losing the weight, with 21700 cell technology. The CORE18V exceeds the power of the original two-layer 4.0 Ah battery with half the number of cells. It features the CoolPack 2.0 heat-management system for extended runtime and battery lifetime.