A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 6110-01-582-4504
NSN 5975-00-655-0761
NSN 5960-01-188-4558
NSN 6220-01-160-7249
NSN 6650-01-473-7723
NSN 6150-00-167-2272
NSN 5930-00-963-6735
NSN 6645-01-030-8930
NSN 7035-01-574-8260
NSN 5855-01-551-7923
NSN 5950-01-134-0827
NSN 5920-01-025-5041