A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 5999-00-351-8804
NSN 5950-01-150-8851
NSN 4140-01-510-0352
NSN 5996-00-715-0837
NSN 5985-00-132-1232
NSN 5960-01-321-2750
NSN 5915-01-362-6987
NSN 5855-00-763-2155
NSN 5975-01-249-7398
NSN 6220-01-528-2153
NSN 5930-00-206-0210
NSN 5950-00-806-0925