Chrome vanadium steel sockets hardened and tempered for added strength fully polished chrome finish for corrosion resistance walldrive configuration giving an additional 30 more torque handling power than traditional sockets knurled ring for extra grip with oily fingers sizes 38sq drive 6 7 8 9 10 11 12 13 14 15 16 17 18mm 12sq drive 19 21 22 24 27 30 32mm supplied with socket rail