Thermaflex®’s Pro Series flexible duct products are the most reliable and durable products in the commercial HVAC industry. All products feature a full 10 Year Pro Warranty, the best in the industry. Flex-Vent offers a complete line of high-quality, value-priced duct products for residential applications and all feature a 10 Year Warranty. Three grades of products, each one a perfect match for a specific application.