A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 6685-01-412-6442
NSN 4140-00-800-3087
NSN 6130-01-132-3756
NSN 6150-00-827-1949
NSN 6620-00-220-2157
NSN 6220-01-423-5559
NSN 6110-00-193-0030
NSN 5835-01-263-1293
NSN 5950-01-611-0083
NSN 5920-01-477-9226
NSN 5985-01-485-7881
NSN 5990-00-518-3195