Less than 0.3 Sones sound level|ULTRA Green 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 Sones level provides nearly silent operation for a relaxing environment, state-of-the-art blower and duct outlet design smooth's 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 1/4 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|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|80 cfm at 0.10 in/1/4 in flow rate|UL listed for use over bathtubs and showers when connected to a GFCI protected branch circuit (ceiling mount only)|Rectangular grille shape