Bosch GDS18V-221B25-RT 18V EC Brushless 1/2 in. The Through-Hole Friction Ring Impact Wrench is designed for driving high-torque bolts, nuts and anchors. This impact wrench features automatic bolt release, which stops rotation when there is no torque on the tool to prevent accidentally dropping bolts and nuts during removal. The tool also has Bosch's hammer and anvil system, which offers high impact energy. The efficient EC Brushless motor boasts a long runtime and delivers up to 221 ft-lbs. of torque, 0-3400 no-load IPM and 0-2400 no-load RPM. This wrench was built with a compact design; It has a 6.4-in. head length and a weight of only 2.77 lbs. Kit includes (2) CORE18V Next Generation 4 Ah Compact Batteries. Each maintains power and runtime, while losing weight, with 21700 cell technology. The CORE18V exceeds the power of the original 4 Ah 2-Layer battery with half the cell count. It features the CoolPack 2.0 heat management system for long runtime and battery life. Impact Wrench Design - Built to deliver high torque for driving fasteners such as lag bolts, concrete anchors and lug nuts Auto Bolt Release - stops rotation when there is no torque on the tool to prevent accidental drop of tool bolts and nuts during removal. Compact CORE18V 4 Ah Li-ion battery - designed to provide next-generation power and runtime, while losing weight, for optimized performance-to-weight ratio Compact tool design - weighs only 2,777 lbs. (tool only, not including battery) and has a 6.4-in. Head Length Ergonomically designed cover and grip a€“ features a soft grip for comfort and keeps tool head cool during use High Power Battery Cells a€“ utilizes enhanced 21700 ce cell technology lulas, combined with an advanced battery design for increased efficiency, to produce longer runtime