The Master Flow 8 in. x 25 ft. Insulated Flexible Duct R6 Silver Jacket is used in standard Heating and Air Conditioning (HVAC) systems and some venting applications. The duct has R6 insulation which contains 33% more insulation than the standard R4.2 product. This additional insulation provides greater thermal efficiency to save energy. The product is also covered in a heavy duty, silver jacket for durability. The duct is ETL listed, meeting the UL181 standard.. R6 fiberglass insulation is perfect for heating and A/C systems. Galvanized core wire resists rust and corrosion. Insulated duct can withstand up to 200°F. <a href="https://quickmeasure.gaf.com/THD" target="_blank" style="color:#F96302;">Don't know how much to order? A GAF QuickMeasure report provides all of the measurement data you need when planning your material orders.&nbsp;A complete bill of materials, with Home Depot product&nbsp;SKUs, is provided with each single-family report delivered in under 1 hour. Learn more here. [gaf.com [gaf.com]]</a>. Flexible duct is convenient for use in multiple applications including heating and A/C systems and some venting. Oversized core to connect quickly and easily to standard sheet metal fitting. Galvanized core wire for greater corrosion resistance vs. non-galvanized wire. Duct can be cut to length as needed. Insulated duct features a maximum temperature rating of 200 degree F. Always install per instructions and seal using approved mastic or sealant (or approved tape). Color: Silver Jacket. Insulated: Yes. Insulation R-Value: 6. Insulator material: Other. Material: Fiberglass. Maximum air flow (CFM): 200. Pack Size: 1. Certifications and Listings: ETL Listed,UL Recognized. Product Depth (in.): 300 in. Product Diameter (in.): 8. Product Height (in.): 11.5 in. Product Length (in.): 300 in. Product Width (in.): 11.5 in. Wall Thickness (in.): 1.75