A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 6105-00-419-9726
NSN 6145-00-050-9919
NSN 5999-01-448-6890
NSN 5915-00-491-0653
NSN 6150-01-444-3582
NSN 5925-00-108-5385
NSN 5960-01-200-4621
NSN 5905-00-432-5859
NSN 5915-01-116-5548
NSN 5905-01-256-1516
NSN 4140-00-935-5360
NSN 2925-00-149-0760