• One of a comprehensive range of Premier Black Hand Tools, suitable for daily professional use. • Manufactured from hardened and tempered high grade Chrome Vanadium steel. • Fully polished black chrome 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: 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 24mm. • Includes knurled ring for extra grip with oily fingers. • Supplied on socket rail. • Lifetime guarantee*.