A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 6220-01-385-4926
NSN 5960-01-278-9394
NSN 6150-00-156-5482
NSN 6220-01-099-3429
NSN 6130-01-535-8824
NSN 6145-01-182-8426
NSN 5965-00-127-3847
NSN 6220-01-386-5006
NSN 6320-01-092-4101
NSN 5960-00-457-1082
NSN 5905-01-477-4786
NSN 5935-01-540-8716