For electric clothes dryers only. Direct valuable heat & humidity back into your home in the dry winter months! Direct the heat & humidity outdoors in the summer! Safety valve eliminates pressure buildup. Dusting not included. During dry winter months much needed heat and humidity will be directed into your house. Stops cold air from leaking back into the house through your dryer. Summer Position: The Heat Keeper directs heat and humidity from your dryer directly outdoors. Winter Position: The Heat Keeper directs valuable heat and humidity into your home through the lint filter. It keeps cold outside air from entering the house through the dryer. Kit Contains: One Heat Keeper air diverter; two 4 in (10.2 cm) adjustable clamps. Made in Canada.