The Mountz PSE450 020187 Preset Torque Screwdriver, 1/4" F/Hex Drive, 8 ozf.in - 40 lbf.in - Gedore 062600 is designed and manufactured to meet or exceed the accuracy and repeatability requirements of ISO 6789: 2003 (+/- 6% of setting). Ergonomic rubber hand grip. Precision radial ball clutch slips-free when the preset torque is reached preventing over-torquing. Tamper-proof internal adjustment. No external adjustment scale - must be preset using a torque analyzer.