A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 6320-00-225-7013
NSN 6135-01-652-4521
NSN 6240-01-261-2861
NSN 5920-01-435-3862
NSN 6135-01-482-7901
NSN 5910-01-214-0626
NSN 4140-00-921-3814
NSN 5910-00-144-4383
NSN 6320-01-111-8851
NSN 5998-01-441-9535
NSN 5945-01-563-2097
NSN 5945-01-042-5736