6-Point Socket Opening – Provides an exact fit and maximum contact for hex fasteners, Fully Stepped Shoulders – The narrowed diameter stretches to the base of the socket on small, deep-length sizes, providing greater reach into tight, recessed areas, Exterior and Interior Finishes – The chrome-plated exterior is highly corrosion resistant and wipes clean to a mirror finish, and the interior is protected against rust with clear coat, Large, Stamped Markings – Markings are permanently impressed into the material by a roll-stamp die and are clearly visible because of their extra-deep outline, Socket Rails – The twist-to-lock clips on the rails hold sockets securely and can be repositioned anywhere along the rails.