GAS Pro Step ControllerOverview The GAS Pro Step Controller is the most efficient AC fan controller on the market. It's easy to use, quiet, and the best way to control your AC fan. Unlike other AC fan controllers, you won't hear any clicking between the 5 steps. It's made at the highest GAS standards and provides growers with an accurate control over the grow room's temperature. Even at lower speeds, there's no vibration or humming from the fan. General Information The unit