Buckley's Type 3 is a top-of-the-line Flexible Duct that's engineered to meet the toughest standards for strength, permeability, and fire safety. This UL-181 Class 1 Air Duct is tailored for use in low- to high-pressure HVAC air systems. Get your 25' insulated Type 3 Fabri-Flex Flexible Duct today!