A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 5905-01-486-6587
NSN 6610-00-253-7676
NSN 5910-01-181-1462
NSN 5990-01-378-7349
NSN 6320-00-553-8427
NSN 5985-00-766-4679
NSN 5855-01-430-9689
NSN 4140-01-166-9289
NSN 5960-00-761-3833
NSN 5855-01-447-3656
NSN 6685-01-206-5218
NSN 5855-01-173-0808