A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 6610-01-109-6405
NSN 5915-01-170-9341
NSN 4140-01-005-0154
NSN 5915-01-459-2109
NSN 7035-00-946-2642
NSN 5996-01-308-4174
NSN 6240-01-593-4245
NSN 6220-00-578-6539
NSN 5915-01-515-2755
NSN 5930-01-394-3738
NSN 2925-01-149-2865
NSN 7035-01-072-1580