We are offering insulation bricks. Features low density high purity low thermal conductivity excellent thermal shock resistance description incertech firebricks are made from high-purity refractory clays, temperature of use ranging from 1100 oc to 1700 oc, each grade is formulated to meet specific thermal and physical requirements. with graduated additions of alumina for higher temperature products carefully grade d organic filler the organic filler burns out during manufacture to give a uniform, control pore structure.