A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 5855-01-197-2774
NSN 6240-00-477-3027
NSN 5945-01-226-9540
NSN 6650-01-481-3618
NSN 5925-00-706-9975
NSN 5965-00-222-7394
NSN 6220-01-181-1154
NSN 5905-01-561-5032
NSN 5855-01-076-5202
NSN 6135-01-395-2388
NSN 6320-01-495-0512
NSN 5998-01-609-7798