An item with an integral porous or perforated plate, or with slits on the inside of a double wall.
NSN 5895-01-204-2128
NSN 6685-01-532-0225
NSN 6610-00-561-5600
NSN 5930-00-269-3666
NSN 5935-01-274-2266
NSN 6105-00-227-1412
NSN 6685-01-142-1969
NSN 2925-00-569-2981
NSN 5950-00-936-5032
NSN 5905-01-152-2580
NSN 6650-01-347-0148
NSN 5985-00-400-3166