For nearly 40 years, Allied International has been committed to satisfying what you look for in Hand Tools. We stand behind everything we build and a Guaranteed Forever warranty for the life of the product. An exclusive feature on all Pro-Grade sockets and combination wrenches, is the Dyne-Drive Torque System, which dramatically improves fastener driving performance when compared to conventional socket and wrench driving systems. By re-designing the socket and wrench box-end interiors to grip the sides of the fasteners rather than the corners (as in conventional tools) the contact surface area is substantially increased. This allows the application of up to 20% more driving torque with no slippages or fastener damage. In addition, many fasteners with existing rounded corners can now be worked more easily.