These 1/2" drive metric sockets have a one-quarter inch square drive that's compatible with drive tools of the same size. - They come in metric sizes that are measured in millimeters to fit fasteners with a metric size head. Socket Size / 23 mm Socket Shape / 12-Point Material / Alloy Steel Finish / Chrome Socket Depth / Standard Drive Type / Hand Drive Size / 1/2 in Measurement Type / Metric Standards / AS4984A, ASME B107.110-2012 Number of Points / 12 Overall Length / 1 17/32 in