3 inch diameter; stainless (1615ss)
A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 6110-00-133-2429
NSN 5925-00-905-2887
NSN 6240-00-865-7447
NSN 6685-01-262-6445
NSN 6145-01-491-6785
NSN 6105-01-370-4141
NSN 5905-01-207-4683
NSN 5975-01-374-2386
NSN 6320-01-326-1316
NSN 5915-00-518-1644
NSN 6220-00-751-9709
NSN 6320-00-779-5923