An item with an integral porous or perforated plate, or with slits on the inside of a double wall.
NSN 6130-01-100-4452
NSN 5998-00-919-0681
NSN 6610-00-946-6146
NSN 6105-01-426-4522
NSN 5895-00-733-5748
NSN 5835-00-892-3510
NSN 5910-01-508-2314
NSN 6145-01-429-8529
NSN 5975-00-169-0513
NSN 2925-01-154-2949
NSN 5960-01-370-4285
NSN 5930-00-789-1992