A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 5960-00-368-4084
NSN 5945-00-110-4548
NSN 5950-00-219-6537
NSN 5965-01-406-3156
NSN 6650-01-462-0830
NSN 6135-01-563-4445
NSN 5975-00-305-8740
NSN 5895-01-064-6180
NSN 5895-01-165-5794
NSN 5945-00-167-2756
NSN 6135-00-073-8939
NSN 5965-01-646-2840