A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 5960-01-294-2397
NSN 6620-01-343-6671
NSN 5996-00-721-2194
NSN 6685-01-208-2132
NSN 5996-01-397-2142
NSN 6620-01-436-3502
NSN 5965-01-078-1312
NSN 5990-01-433-3786
NSN 6685-01-199-1304
NSN 5930-01-300-0345
NSN 7035-00-870-0290
NSN 5915-01-378-6939