A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 5950-01-285-0430
NSN 5930-00-228-0187
NSN 5950-01-573-6434
NSN 6320-00-238-9973
NSN 5990-01-218-5160
NSN 6150-01-400-0692
NSN 6150-00-016-2361
NSN 5998-01-036-2135
NSN 4140-01-445-8199
NSN 6685-00-616-3878
NSN 6110-00-250-7913
NSN 5925-01-398-0517