A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 5990-00-484-1517
NSN 5998-01-467-4394
NSN 4140-00-594-4452
NSN 5910-00-003-5719
NSN 6145-01-423-0382
NSN 5990-00-269-2226
NSN 5965-01-428-3348
NSN 5998-01-258-6469
NSN 6145-00-943-9549
NSN 6105-00-053-2946
NSN 6610-01-167-8747
NSN 5905-01-447-3781