The Suncourt Thru-Wall (through-the-wall) room to room fan TW108 moves cool air in the summer and warm air in the winter. The Thru-Wall Room to Room Fan balances temperatures in adjoining rooms, quietly and efficiently, for year round comfort. The Suncourt Model TW108 Thru-Wall Fan features a 10' grounded power cord and a 3-position rocker switch, which allows you to run the fan at 160 CFM on low and 200 CFM on high. It also has a telescoping housing that allows it to be installed in walls 3 ½” to 6 ½” thick. The TW108 Thru-Wall fan is ETL approved for use in both the United States and Canada.