A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 5915-01-601-7874
NSN 5905-01-363-1730
NSN 5915-01-368-1168
NSN 6110-00-486-0514
NSN 5910-00-271-2323
NSN 5895-01-196-6312
NSN 6110-01-460-4360
NSN 5950-00-943-2717
NSN 6645-01-284-6533
NSN 5855-01-496-6638
NSN 5935-01-578-6295
NSN 5975-00-926-7563