An item with an integral porous or perforated plate, or with slits on the inside of a double wall.
NSN 5965-01-274-7933
NSN 5996-00-839-8678
NSN 5835-01-469-6009
NSN 6130-00-333-5933
NSN 5835-00-814-1359
NSN 5990-01-386-5561
NSN 5895-01-588-8627
NSN 5985-00-170-9097
NSN 6220-00-117-4547
NSN 5835-00-034-4976
NSN 6135-00-078-9931
NSN 2925-01-534-7314