UniTherm Ceramic Bulk Fiber (25 lbs. Per Box) (6-8# Densities, 2300&deg;F) for Vacuum Forming of Rigid Boards & Shapes, Reinforcement of Cast Ceramics, Bulk Fill Material or Insulation and More! Good tensile strength Lightweight Asbestos free Wide temperature range capacity: For use of up to 2300F (1260C) Thermal Shock Resistance & Corrosion Resistance (commonly used acid and alkali).