A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 6610-01-570-3185
NSN 6110-01-652-1900
NSN 5910-01-288-0730
NSN 5915-01-562-4137
NSN 2925-00-347-7893
NSN 5855-01-144-4837
NSN 2925-01-485-6982
NSN 6135-00-405-1989
NSN 6130-01-502-2105
NSN 5935-00-010-0685
NSN 6320-01-425-1417
NSN 5935-00-816-8729