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. Includes knurled ring for extra grip with oily fingers. Supplied on socket rail. 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. Includes knurled ring for extra grip with oily fingers. Contents: 4, 4.5, 5, 5.5, 6, 7, 8, 9, 10, 11, 12, 13, 14mm. Supplied on socket rail. Lifetime