An item with an integral porous or perforated plate, or with slits on the inside of a double wall.
NSN 5835-01-606-8768
NSN 5895-00-216-5849
NSN 6240-00-226-0462
NSN 5910-00-494-7282
NSN 6685-01-400-4192
NSN 6150-01-278-3448
NSN 5945-01-557-6405
NSN 6220-00-361-8338
NSN 6150-01-186-3973
NSN 6150-00-278-1294
NSN 5910-01-593-9114
NSN 5895-01-048-6433