• One of a comprehensive range of Premier Hand Tools, suitable for daily professional use. • Manufactured from hardened and tempered high grade Chrome Vanadium 6142 steel. • Fully polished mirror finish for resistance to corrosion. • Features specially machined flutes in the walls of the socket which enable use on up to 85% rounded fasteners. • This not only provides added strength but also prevents damage to worn or rusted fixings. • Contents: 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4", 13/16", 7/8", 15/16". • Includes knurled ring for extra grip with oily fingers. • Supplied on socket rail. • Lifetime guarantee*.