A high-quality acoustical and thermal insulation. It is composed of long textiletype glass fibers firmly bonded together with a thermosetting resin into a resilient, tough insulation for lining the interior of HVAC sheet metal ducts. The air stream surface is overlaid with a fire-resistant coating which adds strength to the product during fabrication, installation and system operation. It is used primarily as an acoustical liner in HVAC sheet metal ducts to absorb unwanted crosstalk, equipment and air rush noise. It also improves energy efficiency by reducing heat gain or loss. It performs in most types of heating and cooling duct systems, operating at velocities up to 6,000 fpm and temperatures to 250°F. Available in 100' rolls.