The K-Series electric torque screwdriver is an assembly tools that increases productivity and enhances product quality through precision torque control and user comfort. The electric screwdriver automatically stops when the preset torque has been reached. The electric screwdrivers is NRTL certified from TUV America, Inc. The certification ensures manufacturing companies that they are purchasing and operating a quality and safe tool for its operators. Requires STC 30 Plus Transformer (power supply).Model:K250P-A ESD Drive Size:1/4" F/HexRange: 29.4 - 245 cN.m, 2.6 - 21.7 lbf.in, 3 - 25 kgf.cm.Tool Weight:21.2 oz.Tool Length:10.25RPM High:1050RPM Low:630Grip Dia:1 1/2"