Power Grip Self-adjusting Wrenches feature a single-handed operation. Ergonomically contoured and rubber-cushioned handles provide a comfortable grip while a special cam action gripping mechanism increases gripping pressure as the load applied on the handle increases. The 8-Inch and 10-Inch Power Grip hex nut wrenches are made of professional grade, high strength C1045 forged steel and feature specially designed jaws that will prevent slipping and will not round out the corners of nuts and bolts.