3 inch diameter; stainless (1615ss)
A device used to prevent passage of flame through a ventilating duct while air is flowing.
NSN 5999-01-552-0667
NSN 6650-00-283-0978
NSN 2925-01-055-9705
NSN 5965-01-157-2403
NSN 5990-00-135-6180
NSN 6135-01-584-0941
NSN 6220-01-537-6002
NSN 5999-01-469-7684
NSN 5996-00-467-9648
NSN 6320-01-176-8367
NSN 5920-01-377-5803
NSN 6150-01-247-4875