Duraboard 3000 insulation derives its exceptional high-temperature capability from an increased Fibermax fiber concentration in the blend. Fibermax® Duraboard® 3000 insulation, the highest temperature rated board manufactured by Unifrax, provides maximum high-temperature stability and shrinkage resistance. Also formulated from a blend of Fiberfrax alumina-silica fibers and Fibermax, Unifrax’s patented polycrystalline mullite fibers, Duraboard 3000 insulation derives its exceptional high-temperature capability from an increased Fibermax fiber concentration in the blend. This unique formulation controls shrinkage to a level of only 1.2% after 168 hours at 1482°C (2700°F).