A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 6620-01-406-6840
NSN 5895-00-199-0515
NSN 6130-00-519-6192
NSN 5835-01-558-9444
NSN 6620-01-068-4498
NSN 5930-00-862-3515
NSN 6110-01-189-8223
NSN 6620-01-584-6653
NSN 6620-01-169-2406
NSN 5985-00-862-3291
NSN 5935-00-307-3835
NSN 5999-01-627-2686