ULTRA GREEN™ Series 50 CFM Single-Speed Fan, Recognized as ENERGY STAR® Most Efficient 2017 Features: ULTRASMART™ DC Motor and Control Technology  DC motor for efficiency well beyond ENERGY STAR® requirements. Can be used to comply with ASHRAE 62.2, LEED, ENERGY STAR® for Homes and CA Title 24. Powerful operation maintained over a wide range of realworld installations (CFM ratings maintained through at least 0.25” static pressure).  Rated for Continuous Operation.  ULTRASILENT™ Sound Technology  HVI certified, best-achievable <0.3 Sone level provides nearly silent operation for a relaxing environment.  State-of-the-art blower and duct outlet design smooths airflow.  High tech DC motor designed for nearly silent operation.  ULTRAQUICK™ Installation Technology  Unique telescoping mounting frame fits through retrofit drywall opening to allow easy installation from the room side. No attic access needed!  Captive screws allow for easy new construction installation.  Mounting frame positioning tabs provide easy vertical positioning for new construction.  Easy to insert and remove snap-in housing. No screws required!  Easy to insert and remove snap-in blower.  Inside or outside duct connector and knockout plate mounting provides flexibility for new construction or retrofit.  cULus Listed for use over bathtubs and showers when connected to a GFCI protected branch circuit (ceiling mount only). Use only ON/OFF switch, mechanical timer or relay-switched control. 3-year warranty.