Its funny you ask seeing as i just bought a new 8 inch hyper fan and the clerk at the hydro store tried selling me on this but i was not interested atm. But it sounded appealing.
To answer your question, this is directly from Sunlight Supply's website on the controller, "
The Hyper Fan® Speed Controller is extremely easy to use. Set the two dials and you will have complete control of your environment. The Hyper Fan® Fan/Controller combo has the lowest energy use of any fan/controller system out today. The controller thermostatically changes the fans RPM/ Speed as needed. For use with EC Hyper Fans only. All wire connections included."