Woot offers Simple Deluxe 4 Inch 8 Feet Ducting, Non-Insulated Flex Air Aluminum Foil Duct for Dryer Vent Hose, Heating, Cooling, Ventilation, Exhaust, 2 Clamps Included, Silver for $6.69 (orig. $9.99). Free shipping for Prime Members.

Product Description:
Simple Deluxe 4 Inch 8 Feet Ducting, Non-Insulated Flex Air Aluminum Foil Duct for Dryer Vent Hose, Heating, Cooling, Ventilation, Exhaust, 2 Clamps Included, Silver

• High Quality Material: Made of high-quality flame-retardant aluminum, it is resistant to high-temperature(0 - 185°F) and corrosion-resistant. The stainless steel clamps are rustproof, corrosion-resistant and heavy duty, which ensures a seamless junction.
• Perfect Connection: Simple Deluxe ducting is primarily used with duct fan systems in various air circulation and ventilation projects, to move and transport air, which increasing airflow and easing connections between spaces.
• Multi-Layer Protection: Duct features four-layer protection, which is much more durable and resistant to leak than single-layer ones. Internal & outer layers are made of flame-retardant heavy-duty aluminum foil, which protects the ducting from tearing.
• Easy to Install: Flexible ventilation ducting can be cut to the required length according to the needs, comes with 2 duct clamps in the same duct opening size for easy setup and securer connection.
• Wide Applications: Aluminum duct is widely used in various air circulation and ventilation projects, including hydroponic planting rooms and tents, bathrooms and lofts, closets, racks and cabinets, heating and cooling transportation and other devices.