Bionaire Premium Digital Twin Window Fan creates a comfortable cool and refreshing environment for your home living spaces. Features reversible 8.5" dual fan blades with independent control settings to draw in fresh air from outside, exhaust out hot air from inside, or exchange airflow simultaneously. The programmable thermostat with an easy-to-read LED screen lets you select a desired room temperature and the fan will automatically turn on and off to maintain the selected comfort level. Feel the breeze with 3 speeds settings, low, medium and high to create your optional airflow. Designed to fit most double hung and vertical slider windows and has a built-in accordion extender panel and an additional extender panel to ensure a custom fit for various sizes. Ideal for use in bedrooms, kitchens, living rooms and home offices and includes a convenient remote control to operate from across the room. No assembly required, modern light grey finish and 3-year limited warranty.