A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 2925-01-423-8141
NSN 5930-00-607-0814
NSN 5920-00-397-2212
NSN 5960-00-223-5970
NSN 6135-00-078-9931
NSN 5975-01-501-0352
NSN 5925-01-228-9058
NSN 6150-00-954-4549
NSN 6650-00-221-9425
NSN 5998-01-263-5260
NSN 5960-00-800-7118
NSN 6645-01-574-1969