No. 18 spline size
An item having an internal drive at one end made to fit into the external drive end of a socket wrench handle, torque wrench, or power driven tool. The opposite end consists of various internal wrench shapes such as hexagon or square. It may include an integral universal joint.
Classification: Socket wrenches with or without handles, drives and extensions, parts, base metal
NSN 6150-00-098-5874
NSN 6110-01-525-5304
NSN 5998-01-177-2229
NSN 5960-00-136-7046
NSN 5855-01-631-5051
NSN 6320-01-272-7072
NSN 5895-01-566-9080
NSN 6650-00-500-6455
NSN 5975-01-451-7623
NSN 6150-01-533-9116
NSN 5975-01-420-7477
NSN 6650-01-604-9073