4” LIGHTPROOF DUCTING - We made this aluminum 4 inch duct with your Grow Room needs in mind. Thick layer of Black PVC on this ducting prevents light leaks. This flexible duct works with exhaust and intake fans, carbon filters and hooded lights which are 4" in diameter 4 LAYER PROTECTION- Our 4 inch duct hose Keeps your ventilation system free of rips, pin holes and resistant to leaks. Under the White PVC layer our ducting is built with 2 layers of Aluminum Foil With a layer of PET and Steel Wire Helix to preserve the shape FLEXIBLE & EASY TO USE- TerraBloom 4 inch air ducting is super flexible and easy to install. It will slide right on your Duct Fan, Vent Exhaust, Carbon Filter or Light Reflector. We include a pair of 4 Inch Clamps to make the installation a breeze 4" DIAMETER WITH ADJUSTABLE LENGTH- This 4 inch flexible duct comes in one 25 Feet Long Piece, which can be cut into as many pieces as you need using a wire cutter and a paper knife APPLICATIONS - TerraBloom 4inch duct is suitable for any Heating Ventilation & Air Conditioning (HVAC) Purposes. It will move and deliver air in Kitchens (cooking exhaust), Green Houses and Grow Rooms (Air Circulation, Intake, Exhaust and Light Fixture Cooling), Bathrooms (Smell and Moisture Exhaust), Dryer Rooms, Grow Tent ducting and other applications you have in mind