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 5950-01-425-1174
NSN 6620-01-288-8249
NSN 6105-01-442-3465
NSN 6650-01-444-2152
NSN 6145-00-910-8847
NSN 6220-01-256-9835
NSN 5920-01-412-3787
NSN 6650-01-369-1650
NSN 5975-00-162-9530
NSN 5925-01-335-4415
NSN 5925-01-372-9519
NSN 5930-00-818-5600