A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 5990-01-563-1554
NSN 5835-01-436-6549
NSN 6645-00-171-9639
NSN 5925-01-429-7699
NSN 5915-01-444-4069
NSN 6610-01-242-3760
NSN 5915-01-249-6448
NSN 5935-01-010-3415
NSN 6105-01-234-3545
NSN 5985-01-151-3224
NSN 5855-01-444-9182
NSN 6110-01-513-9907