The 2000 SR Series Ducting is specifically engineered to handle unconditioned are. The 2000 SR Series can withstand high heat, high humidity and excessive CFM's without any duct failure or fatigue. 2000 SR features a triple laminate with industrial grade foil casting for durability, and an ultra-smooth double sealed core for frictionless and silent air flow. The "Carbon Black" inner core does not reflect light. "Rip-stop" prevents tearing, galvanized spring steel maintains duct shape and prevents rust. The SR Series is c-ETL-us certification tested and verified to conform to UL181 standards. Made in Canada! North America's best quality product. It's engineered for what you need.