A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 6240-01-423-5510
NSN 5985-00-293-5684
NSN 6145-00-553-8196
NSN 6320-01-407-8663
NSN 5925-01-238-5711
NSN 5945-01-354-2832
NSN 5996-01-127-5431
NSN 5925-00-896-0350
NSN 5910-00-587-4791
NSN 5999-00-435-0417
NSN 5920-00-459-4522
NSN 5895-01-040-3634