An item with an integral porous or perforated plate, or with slits on the inside of a double wall.
NSN 5930-01-492-5220
NSN 6685-00-773-5731
NSN 5950-00-482-4078
NSN 5895-00-280-7528
NSN 5895-00-054-7509
NSN 5950-00-577-4336
NSN 6145-01-094-6108
NSN 7035-01-012-2259
NSN 6620-01-305-0412
NSN 5945-00-753-7716
NSN 5835-01-376-5233
NSN 5990-00-689-5736