The Craftsman Extreme GRIP 5-piece socket set (Model #25805) features a gripping action which allows you to grip rounded fasteners up to 14-times better than a standard Craftsman socket. Each socket features movable jaws to provide solid fit for standard, metric and rounded fasteners. Serrated jaws grip onto rounded fasteners. Release collar for easy disengagement. This 5 piece socket set can be used on the following 10 fastener sizes: 7/16", 1/2", 9/16", 5/8", 11/16" 11mm, 13mm, 14mm, 16mm and 17mm. This set is backed by the Craftsman Hand Tool Full Warranty.