A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 5998-01-421-4170
NSN 6110-01-304-7679
NSN 6145-01-513-6352
NSN 6650-01-279-0658
NSN 6150-01-108-6153
NSN 5945-00-725-4552
NSN 6105-01-211-6635
NSN 5990-00-859-2932
NSN 7035-01-073-9424
NSN 6650-01-386-5787
NSN 5950-01-158-5637
NSN 7035-01-214-5171