A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 5835-00-827-1904
NSN 5855-01-175-0284
NSN 4140-01-109-5112
NSN 6650-01-423-2834
NSN 6685-01-421-4403
NSN 5920-01-604-9045
NSN 5895-01-546-5283
NSN 6645-01-437-5290
NSN 5999-00-248-3227
NSN 5920-01-290-3771
NSN 5905-00-604-0388
NSN 5895-01-009-2812