A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 5835-00-918-3720
NSN 5910-01-502-9833
NSN 5996-01-532-0536
NSN 6610-01-141-7014
NSN 5990-01-463-2279
NSN 5920-00-362-1376
NSN 5975-01-415-3331
NSN 5999-00-372-5709
NSN 5999-01-643-2870
NSN 5855-00-973-5717
NSN 5960-01-544-1273
NSN 5905-01-492-1106