Use with a 1/2" drive tool to install various engineering fasteners that require a specified angle application after a pre-torque load has been applied. The gauge is calibrated in 5" increments with a rotating pointer. Use a 1/2" male and female square drive and an adjustable holding rod to hold gauge in position during use. The gauge is packaged in a convenient storage pouch, more and more manufacturers are using the torque angle procedure for tightening fasteners and head bolts, simply because it's a more accurate way to ensure even tightening on the widely used aluminum heads and blocks. This torque angle gauge will guarantee a more precise method of tightening fasteners. The easy-to-read gauge lets you see exactly where you are in your turn procedure.