4'' Air Duct - 4" x 25' Our Air Ducting features a high-quality, light-proof, aluminum construction that is perfect for use in various applications. The spring steel wire helix design, allows for a high degree of flexibility for easy installation and resists punctures and tearing. Perfect for intake and exhaust piping, our Air Ducting dissipates heat at a steady rate, reducing room temperature fluctuations. All of our Air Ducting is specifically oversized by 3/8 in to fit any application. Specifications Ducting Size: 4 Inch (Diameter) x 25 Feet (Length) Fully Extended Thermal Endurance: Temperature endurance range from 0 ~ 185°F.(-18℃ ~ 85℃) Wide Range of Applications: Kitchens, Bathrooms, Greenhouses, Grow Rooms, Grow Tents, etc. Fire Proof Coating: Flexible ventilation ducting made from high-quality flame resistant aluminum and built-in corrosion-resistant wire helix for reinforcement and lasting performance.