A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 5925-01-205-1773
NSN 5915-00-850-0215
NSN 5998-00-456-0864
NSN 6240-01-512-1856
NSN 5895-01-090-0567
NSN 6610-00-104-9737
NSN 5975-00-613-2345
NSN 4140-01-441-1307
NSN 6610-01-629-4140
NSN 5905-01-514-7467
NSN 6110-00-168-8609
NSN 6150-00-617-1989