4" DUCT - LIGHTPROOF and HEAT RESISTANT:We made this aluminum duct with your Grow Room needs in mind. Thick layer of White PVC on this ducting prevents light leaks and repels heat from your light fixtures to keep the air cool. Works with exhaust and intake fans, carbon filters and hooded lights which are 4" in diameter 4-LAYER TOUGH:Keep your ventilation system free of rips and pin holes. 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 AND EASY TO USE:Our 4 Inch Duct 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 Ventilation Duct is 4 Inches in diameter and 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 VARIETY OF APPLICATIONS:Our Ducting 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 Tents and other applications you have in mind