AP Products (013-3100-M 4" x 25' Flexible Air Duct Flex hose Ultra 10 core with 2 ply, polyester - metalized polyester Versatile air connector for a multitude of low to medium pressure HVAC applications Well suited for main trunk lines, supply and return lines, connecting lines, plus runs to diffusers, room registers, and other terminal devices in spaces where insulation is not required Great for venting and exhaust applications The outer layer is also metalized for aesthetics UL Rated operating temperature: -20 Degree Fahrenheit up to 180 Degree Fahrenheit, -29 Degree Celsius up to 82 Degree Celsius Clamps not included