As differentiated by quality control iaw mil-q-9858
A fluid line fitting having a pipe, tube or hose connection or a through hole to accommodate a bolt, fluid passage on one end. The other end must have an external or internal thread for connecting a mating part to form a self-sealing coupling assembly. The fitting has either a self-sealing feature for the purpose of automatically shutting off the flow of fluid when disconnected from its mating half, or, if it has no self-sealing feature, is specifically designed to mate with a fitting with a self-sealing feature. For self-sealing fittings with a quick disconnect end, see coupling half, quick disconnect. For fluid line fittings without a self-sealing feature, see coupling (as modified).
NSN 6110-01-577-2571
NSN 6105-01-608-3125
NSN 6240-01-394-8592
NSN 6620-01-507-5283
NSN 6105-01-466-4936
NSN 5905-00-674-7021
NSN 6320-00-270-8222
NSN 5990-01-548-3711
NSN 5905-00-075-4671
NSN 5910-01-292-0560
NSN 6320-01-291-4870
NSN 5855-00-107-7993