A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 6610-00-735-2295
NSN 5965-01-597-0922
NSN 6220-00-284-0910
NSN 6620-00-770-9794
NSN 6620-01-111-9064
NSN 6685-01-532-6934
NSN 5945-01-245-9358
NSN 6240-01-030-4746
NSN 6645-01-512-2220
NSN 5990-01-443-2931
NSN 6650-01-076-9124
NSN 6145-00-774-4579