An item with an integral porous or perforated plate, or with slits on the inside of a double wall.
NSN 6620-01-350-0323
NSN 5965-01-314-3253
NSN 6135-01-512-8740
NSN 5965-00-990-8669
NSN 5895-01-398-7303
NSN 6685-00-212-4531
NSN 5998-01-360-4879
NSN 6110-01-431-6906
NSN 5996-01-170-9659
NSN 5996-00-813-7422
NSN 5950-00-669-8565
NSN 6620-00-280-2874