Olympia Tools 01-160 2-Pieces Power Grip Set, 8-Inch and 10-Inch Hex Nut Wrenches Self-adjusting within the capacity range of each size wrench Special cam action gripping mechanism increases gripping pressure as the load applied on the handle increases. Specially designed jaws will prevent slipping Reduces fatigue - up to 50percent lighter than traditional cast iron pipe wrenches Fast and easy thumb actuated jaw release