Forged Chrome Vanadium steel 1/4", 3/8" & 1/2" Sq drive sockets with S2 steel spline bits. 1/4" Sq Drive: 4, 5, 6mm, 3/8" Sq Drive: 8, 10, 12mm, 1/2" Sq Drive: 14, 16mm. Knurled ring to assist gripping of socket with oily fingers. Supplied on socket rail. Model No. AK6214