Reflectix® Duct Insulation consists of two layers of highly reflective film (94%+ reflectivity) that are bonded to two tough layers of polyethylene. Two inner layers of insulating bubbles resist conductive heat flow while a center layer of polyethylene gives Reflectix® high reliability and strength. The product has a tape running the length of the roll for easy identification by code officials. Reflectix Duct Insulation, 100 ft Length, 60 in Width, 5/16 in Thickness, 500 sq-ft Coverage, -60 to 180 deg F, Polyethylene, Domestic