Permacote Linacoustic® R-300 is a rigid fiber glass board that meets or exceeds all ASTM C 1071 Type II duct liner requirements. The airstream surface and the long edges are coated with a tough, smooth, state-of-the-art acrylic polymer. R-300 is specifically designed for use as an extended performance lining insulation for HVAC plenums and air distribution ductwork. It offers exceptional durability and superior acoustical and thermal performance in systems operating at velocities up to 6,000 fpm (30.5 m/sec) and temperatures up to 250°F (121°C). Linacoustic R-300 has been certified by Scientific Certification Systems to contain 25% recycled content (minimum 20% post-consumer).