A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 6685-00-951-3498
NSN 6685-00-392-0940
NSN 6145-01-481-3688
NSN 5910-01-255-6365
NSN 5895-00-316-5667
NSN 5835-00-269-2232
NSN 5985-00-443-3637
NSN 6650-01-210-5090
NSN 5950-01-242-9896
NSN 5945-00-418-3136
NSN 6130-01-223-4135
NSN 5975-00-827-1107