By presetting the built-in thermostat the fan will operate at one of three preselected speeds when the thermostat calls for cooler air. Once the thermostat is satisfied the fan automatically shuts off. Fan will not operate unless dome is open. Vent lids are lifetime guaranteed. Reverse with thermostat.

 PROP 65 WARNING: This product may contain chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. Wash hands after handling. For more information, visit www.P65Warnings.ca.gov