This set is ideal for getting into those awkward places that are just impossible to get at with normal sockets. Manufactured from Chrome Vanadium Steel, heat treated and hardened with mirror polished finish. Supplied on spring tensioned clip-rail. Size: 10,11,12,13,14,15,16,17,18 & 19mm Sprung tensioned socket rail. Manufactured from Chrome Vanadium Steel. Heat treated. Hardened. Mirror polished finish.