A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 5985-01-032-6251
NSN 6620-01-406-3584
NSN 5999-01-286-3054
NSN 5915-01-555-8852
NSN 6150-01-147-0359
NSN 5999-01-004-4043
NSN 6105-00-690-6528
NSN 5998-00-468-5022
NSN 6130-00-395-0778
NSN 6135-00-593-6831
NSN 6645-01-380-1189
NSN 5930-01-040-4329