METRIC, ¼” drive, Double Square, Standard Length, Chrome Hand Sockets.    Double Square socket:  Drive with 8 equally spaced sides, each with a 90 degree angle. The 8 equal sides allow for easy alignment to square head bolts. Input Drive Size: 1/4" Drive Shape: Square Length: 22mm Type: Double Square Socket Output Size 1/4 Sq. Dr. Socket 10mm Double Square Length 22mm