WhisperGreen Select Pick-A-Flow 30 to 110 CFM Bathroom Exhaust Fan Flex-ZFast Bracket-4/6 in. Duct Adapter

The WhisperGreen Select fan operates quietly at an "always on" low speed to maintain fresh air and increases to a higher speed when activated by a switch or sensor; it automatically returns to low speed after a user-set time. The only residential vent fan series with a combination of certified CFM performance at 0.5 w.g. and low sone levels, the WhisperGreen's superior performance exceeds industry standards set by ASHRAE and ENERGY STAR. Flex-Z Fast Bracket simplifies installation with a single-hinge bracket for easy positioning so you don't need to access your attic to install the fan and includes options for 4" or 6" ducting. Ideal for use in the bathroom, laundry room, sun room, basement or garage. Can accommodate up to 2 more add-on modules including Wi-Fi, Smart Action Motion Sensor, and Condensation Sensor