An item with an integral porous or perforated plate, or with slits on the inside of a double wall.
NSN 5910-01-030-2943
NSN 5996-01-641-7919
NSN 6645-01-523-7171
NSN 6110-01-520-9911
NSN 5930-01-125-7319
NSN 5905-01-563-7917
NSN 6105-00-420-1047
NSN 6150-00-353-7392
NSN 5935-00-554-0244
NSN 6130-01-343-8136
NSN 5990-00-730-4366
NSN 5925-01-228-9058