A cylindrically-shaped headed item, having circular or longitudinal groove(s).
NSN 5925-00-171-0307
NSN 5975-01-550-9090
NSN 5915-01-193-1952
NSN 5920-00-137-5003
NSN 4140-01-232-0537
NSN 6145-01-019-0773
NSN 6110-01-633-9660
NSN 6110-01-519-9131
NSN 6220-01-519-8385
NSN 6685-01-132-0939
NSN 6220-01-268-0570
NSN 6320-00-857-4073