A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 4140-01-463-3295
NSN 6150-01-406-5400
NSN 6135-01-400-2947
NSN 5855-00-995-2098
NSN 5975-01-578-3904
NSN 5960-00-443-9452
NSN 2925-01-560-4123
NSN 6145-00-915-5546
NSN 5999-00-679-9934
NSN 5990-00-740-0249
NSN 5975-01-280-3904
NSN 5910-01-430-0017