Bosch, 18 Volt, EC Brushless 1/4 in. and 1/2 in. Two-in-One Bit/Socket Impact Driver Kit with 2.0 Ah SlimPack Battery. Half driver, half wrench has a 1/4 in. quick-change hex shank and a 1/2 in. square drive, for using either bits or sockets. Powerful EC Brushless motor delivers a max of 1,800 in. lb. of torque and up to 4,200 ipm for professional power. Impact driver eliminates using socket adapters, while transmitting more torque directly through the 1/2 in. square drive anvil. One 18 Volt 2.0 Ah SlimPack battery and charger provide outstanding runtime.