A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 6110-01-098-5071
NSN 5920-01-057-8529
NSN 5999-01-414-7667
NSN 6650-00-067-3572
NSN 5835-00-859-8330
NSN 5975-00-859-7009
NSN 5960-01-306-4606
NSN 6145-01-421-2458
NSN 5895-01-457-9260
NSN 5925-01-530-5757
NSN 5855-01-384-4914
NSN 6110-01-050-8119