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 6645-01-336-6631
NSN 6110-01-089-9017
NSN 6610-01-227-7221
NSN 5910-00-584-4614
NSN 5998-01-571-8462
NSN 6150-00-661-0184
NSN 6240-00-471-5399
NSN 6150-00-478-5880
NSN 6135-01-034-5202
NSN 5999-00-497-2140
NSN 6240-01-435-3892
NSN 6610-01-575-4348