A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 5945-01-599-8450
NSN 4140-00-738-2640
NSN 5999-00-222-7428
NSN 5998-01-481-2036
NSN 5910-01-555-0086
NSN 5999-01-435-5734
NSN 7035-00-140-0474
NSN 6620-01-386-5543
NSN 5905-01-468-6057
NSN 5985-01-462-6610
NSN 5990-01-321-2997
NSN 5990-01-565-2226