A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 2925-00-211-4761
NSN 6130-00-111-4796
NSN 6105-01-252-8847
NSN 5920-01-473-6745
NSN 6650-01-204-2524
NSN 6240-00-886-3278
NSN 6650-00-015-1835
NSN 5965-00-665-2156
NSN 5996-00-146-1275
NSN 5985-01-401-5387
NSN 5960-01-573-6483
NSN 5935-01-303-4754