A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 5945-01-101-6089
NSN 6650-01-049-1881
NSN 4140-01-367-2547
NSN 6110-01-468-5153
NSN 5905-01-333-8813
NSN 4140-00-528-2921
NSN 5910-00-787-0351
NSN 6240-01-495-3676
NSN 5998-01-483-2001
NSN 5910-01-005-2612
NSN 7035-01-338-9971
NSN 5895-01-147-4767