A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 7035-00-553-6951
NSN 6320-00-300-5556
NSN 6145-01-167-8366
NSN 4140-01-414-4551
NSN 4140-00-260-9521
NSN 7035-01-435-7962
NSN 6685-01-029-3773
NSN 5895-01-281-0072
NSN 6220-01-415-0926
NSN 6130-01-414-3497
NSN 6150-00-572-9154
NSN 6135-00-050-7189