A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 6220-01-646-6342
NSN 7035-00-570-4100
NSN 6240-00-364-0850
NSN 6645-00-181-1877
NSN 6105-01-634-0322
NSN 6320-01-249-3236
NSN 5915-01-426-8862
NSN 6150-01-469-8136
NSN 6105-01-172-7640
NSN 6145-00-470-1606
NSN 5920-01-288-0145
NSN 6150-00-259-4632