A brick having a low thermal conductivity and used as a backing for the more dense refractory brick.
NSN 5915-00-435-3467
NSN 5985-01-525-3746
NSN 5998-00-205-8803
NSN 5998-00-820-5818
NSN 5935-00-134-1490
NSN 5855-01-213-0783
NSN 5895-00-479-8547
NSN 6610-01-187-1748
NSN 7035-01-527-7023
NSN 6130-00-651-7326
NSN 5960-01-632-6576
NSN 5996-00-142-9033