A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 5960-01-032-4229
NSN 4140-00-983-4083
NSN 6320-01-323-7565
NSN 5990-00-226-1152
NSN 6220-01-026-2424
NSN 5855-00-832-9341
NSN 5950-00-987-3531
NSN 6650-01-609-0953
NSN 6150-01-481-3473
NSN 5920-00-821-0078
NSN 5985-01-309-5120
NSN 5920-01-254-2753