Manually Reversible Twin Window Fan, Can Be Positioned For Intake Or Exhaust, Slim Profile To Maintain Outside View, Expander Panels For Custom Fit, 2 Quiet, Energy Efficient Speeds, Fully Assembled For Window Use, Snap On Feet Included For Floor Or Table Use, Fits Windows From 22" To 34", Double Hung, Casement, Sliding, ETL Listed.