The Mountz Gedore PSE Preset Torque Screwdriver 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.