A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 6105-00-079-2409
NSN 2925-00-504-0913
NSN 6610-00-802-8057
NSN 5905-01-543-8214
NSN 5965-01-446-1512
NSN 5950-00-288-0208
NSN 7035-01-485-0269
NSN 6110-01-298-0975
NSN 5950-01-528-7982
NSN 6145-01-444-1668
NSN 5915-01-537-0605
NSN 5925-01-476-3879