Deflecto Extra Heat Dryer Saver, 4", White (EX12) 4" diameter dryer to vent hose Use with UL listed supurr-flex clothes dryer transition duct (not included) Saves the heat from your clothes dryer and diverts it into your room. Deflects heat and humidity into the home in cold weather, deflects heat outside during warm weather Saves energy and money. Clean filter screen after each use for optimal performance and safety Do not vent gas clothes dryer into batroom or bedroom Converts Clothes Dryer Into Extra Source Of Heat Includes Diverter To Allow Exhausting Outside During Warmer Weather Safety Flap Allows For Outside Venting