A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 6645-01-633-1852
NSN 5905-01-134-7458
NSN 6150-00-614-2132
NSN 6110-01-090-0804
NSN 6240-01-163-2813
NSN 6150-01-507-4910
NSN 6240-00-555-6347
NSN 5895-01-541-5379
NSN 5905-01-591-4744
NSN 7035-00-546-2560
NSN 5945-01-461-8494
NSN 4140-01-540-3201