A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 5950-00-019-2767
NSN 5965-01-267-8536
NSN 6105-01-235-9100
NSN 6105-00-925-0519
NSN 6685-01-250-2669
NSN 5895-00-548-9329
NSN 6620-00-092-7383
NSN 6240-01-384-4868
NSN 5960-01-512-0233
NSN 5996-01-323-6008
NSN 6240-00-334-6766
NSN 5935-01-447-2977