An item with an integral porous or perforated plate, or with slits on the inside of a double wall.
NSN 5930-01-565-8423
NSN 6685-01-424-0975
NSN 5998-01-381-3741
NSN 6145-01-429-6070
NSN 6105-01-183-5484
NSN 7035-00-946-2642
NSN 5925-00-606-6529
NSN 5915-00-260-3791
NSN 5915-01-604-9868
NSN 5905-00-174-7845
NSN 2925-01-517-8544
NSN 6110-00-989-4629