A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 7035-01-027-2259
NSN 5925-01-245-6481
NSN 2925-01-609-3525
NSN 5999-01-118-6871
NSN 5905-01-443-7941
NSN 6645-00-081-4298
NSN 6620-00-663-8962
NSN 6110-01-424-0612
NSN 6610-01-023-1918
NSN 6110-01-443-8770
NSN 5990-00-688-7771
NSN 6150-00-536-4104