Chrome Vanadium steel Total Drive® sockets, hardened and heat treated for strength with a fully polished mirror finish for resistance to corrosion. Can be used on a wide range of fasteners. All are suitable for Spline, Metric Hex and Bi-Hex, with many also equivalent to TRX-Star*, Whitworth, Imperial Hex and Imperial Bi-Hex. Knurled ring for extra grip with greasy fingers. Supplied on rail. One of a comprehensive range of Premier Hand Tools, suitable for daily professional use. Chrome Vanadium steel Total Drive® sockets, hardened and heat treated for strength with a fully polished mirror finish for resistance to corrosion. Can be used on a wide range of fasteners. All are suitable for Spline, Metric Hex and Bi-Hex, with many also equivalent to TRX-Star*, Whitworth, Imperial Hex and Imperial Bi-Hex. Sizes: 4, 4.5, 5, 5.5, 6, 7, 8, 9, 10, 11, 12, 13, 14mm. Knurled ring for extra grip with greasy fingers. Supplied on rail. Lifetime guarantee*.