This International Standard is applicable to the driving parts of hand-operated square drive socket wrenches identified in ISO 1703 under designations 6 1 00 04 0, 6 1 00 06 0, 6 1 00 06 1, 6 1 00 09 0, 6 1 00 10 0, 6 1 00 10 1, 6 1 00 01 0, 6 1 00 01 1, 6 1 00 03 0, 6 1 00 05 0 and 6 1 00 05 1. NOTE These designations correspond to the former (old) designation numbers 253, 255, 256, 257, 251, 252 and 254.It specifiesa) the overall dimensions, b) the minimum Rockwell hardness value for their squares, c) the method of torque testing, d) the minimum torsional strength values, e) the method endurance of testing for ratchet handles, f) designation, and g) marking.