A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 5895-00-110-0938
NSN 5915-01-606-8569
NSN 5855-01-548-1763
NSN 5935-01-008-1975
NSN 6150-01-144-0774
NSN 5950-00-252-7065
NSN 5915-00-740-4336
NSN 5965-01-100-5283
NSN 6620-01-556-9512
NSN 5915-01-359-2573
NSN 5960-01-605-9921
NSN 6130-01-537-1261