An item with an integral porous or perforated plate, or with slits on the inside of a double wall.
NSN 5905-00-236-1328
NSN 5920-01-343-2769
NSN 6320-01-311-3286
NSN 6240-01-032-5105
NSN 6130-01-050-2480
NSN 5905-01-579-3060
NSN 7035-01-526-6775
NSN 5965-00-922-6243
NSN 5910-01-006-1429
NSN 6110-01-533-7768
NSN 6105-01-413-8342
NSN 6130-01-628-4533