A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 6320-01-422-1212
NSN 4140-01-104-4727
NSN 6610-01-535-8757
NSN 6110-01-442-6665
NSN 5960-01-127-5425
NSN 4140-00-828-7113
NSN 5920-00-252-3197
NSN 6645-01-504-2301
NSN 4140-00-484-4040
NSN 7035-01-601-3772
NSN 6685-01-004-3614
NSN 5935-00-902-5838