eep cool on warm days with the Holmes Twin Window Fan (model HAWF2021), which is designed to fit into most double hung and slider windows. The twin 7-inch blade operation circulates air more effectively than other single-blade window fans, and the 2 quiet fan speeds make it ideal for use in living rooms or bedrooms. Other features include a manual reverse function to take hot air out of a room, an adjustable extender screen, and bonus extender panel that enable an easy fit into windows that measure 24 to 36 inches wide.