A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 6610-00-793-0010
NSN 6105-00-404-1637
NSN 5905-01-629-9570
NSN 5985-01-105-6712
NSN 6145-00-061-6866
NSN 5935-01-359-8962
NSN 7035-01-542-3276
NSN 5965-01-548-0965
NSN 6110-01-213-3246
NSN 5920-00-368-4151
NSN 6645-00-841-0026
NSN 5945-01-535-6385