An item with an integral porous or perforated plate, or with slits on the inside of a double wall.
NSN 5996-01-382-5113
NSN 5975-01-013-2391
NSN 2925-01-100-3694
NSN 6130-00-509-1591
NSN 5998-01-119-4189
NSN 6320-01-166-3602
NSN 6650-00-161-4122
NSN 5945-01-243-8776
NSN 7035-01-341-4310
NSN 5960-01-036-3839
NSN 6645-01-485-3517
NSN 5905-01-453-1716