UltraGreen energy saving DC motor: Efficiency well beyond Energy Star requirements, Can be used to comply with Ashrae 62.2, LEED, Energy Star for Homes and CA Title 24; UltraSilent sound technology: HVI certified best-achievable lesser than 0.3 sone level provides nearly silent operation for a relaxing environment, state-of-the-art blower and duct outlet design smoothes airflow, high tech DC motor designed for nearly silent operation; UltraSmart control technology: Powerful operation maintained over a wide range of real-world installations ( CFM ratings maintained through at least 0.25 IN SP), rated for continuous operation; UltraQuick installation technology: Unique telescoping mounting frame (Spans upto 24 IN on-center framing) 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; 3 YR warranty