The ThruWall Room to Room Fan balances temperatures in adjoining rooms, quietly and efficiently, for year round comfort. Interior use only - not intended for ventilating moisture from bathroom.Features:• Quiet operation • Variable speed adjustable: From 200 CFM on high speed to 100 CFM on low speed • The ThruWall"s telescoping housing installs in frame walls from 3½" to 6½" thick • Rotating grill allows airflow direction to be changed for comfort • Back grill diameter: 9-3/4" • 12 month limited warranty• Fan diameter: 8 inchesSpecifications:Weight - 5 lbsAmps - .85CFM - 200 on High Setting / 100 on Low SettingFront Grille Dimension - 12-1/2" x 10"dBA - High - 55 / Low - 49 Sones: 3INSTALLATION NOTES:Hole of approximately 11 1/4" X 8 3/4" must be cut in wall on output side to accomodate fan and electrical assembly; hole for suction side is approxiamately 8 7/8" in diameter. Cutout template included with fan. Unit has built-in electrical box and must be hard-wired, and does not come with plug.Do not install in wet locations REAR VIEW