An item with an integral porous or perforated plate, or with slits on the inside of a double wall.
NSN 5855-00-174-3482
NSN 5950-01-563-2012
NSN 6135-01-247-5660
NSN 6320-00-725-0754
NSN 4140-01-497-9992
NSN 6145-01-551-7902
NSN 5945-01-372-3519
NSN 5998-01-550-5623
NSN 6105-01-020-9013
NSN 6610-00-731-2649
NSN 5930-01-270-3588
NSN 5999-01-025-5337