VIVOSUN 4 Inch 25 Feet Non-Insulated Flex Air Aluminum Ducting for HVAC Ventilation w/Two 4 Inch Stainless Steel Clamps Ducting Material: High-quality aluminum (High Temperature Resistant & Corrosion Resistant & Long Lasting); Clamps Material: Stainless steel (Rustproof & Corrosion Resistant & Heavy Duty). Ducting Feature 1: Three-layer Thickness (Aluminum Foil + PET + Aluminum Foil): Flame-retardant coating. Thermal Endurance: Temperature range from -22 to 266 Fahrenheit. Ducting Feature 2: Built-in steel wire for reinforcement and long lasting performance. Ducting Feature 3: Flexible length for exhaust fan blower / inline fan; quick and easy to set up. Application Scenarios: Perfect for Heating Ventilation & Air Conditioning (HVAC), Kitchens, Bathrooms, Greenhouses, Grow Rooms, Grow Tents, etc.