For nearly 40 years, allied International has been committed to satisfying what you look for in hand tools. Pro-Grade wrenches are built to stand up to the toughest work conditions. Combinations, open end and flare nut styles are hot drop-forged from chrome vanadium Alloy, then heat treated for optimum strength. Box ends are precision Broached and chamfered for a smooth, secure fit and featured the dyne-drive torque system which dramatically improves performance when compared to conventional wrench driving systems. The board, flat paneled beams are smooth edged, then nickel-chrome plated and polished to a mirror finish. This allows the application of up to 20% more driving torque with no slippage or fastener damage. In addition, many fasteners with existing rounded corners can now be worked more easily. The results are a wrench that instantly conveys a message of exceptional quality and workmanship.