An item with an integral porous or perforated plate, or with slits on the inside of a double wall.
NSN 6130-01-267-3512
NSN 6320-01-350-5570
NSN 5915-01-011-9576
NSN 5996-01-357-7535
NSN 5996-01-304-1088
NSN 5835-01-647-6426
NSN 6610-00-410-0940
NSN 6220-00-186-8565
NSN 6145-01-640-6511
NSN 6150-00-190-5054
NSN 6240-01-303-0142
NSN 6150-01-169-7380