The Gavita Master Controller EL2 can switch interconnected fixtures on and off with the internal timer. This allows you to adjust your grow room to your required output level. This can take place of lighting timers and contactors all while ballast current in-rush when you switch the lights on. Key features of this system include the auto-dim function and emergency shut down. The temperature probe allows for your grow space to be protected against temperature damage. This ensures that you don't overshoot the safe temperature for your plants. The LED display indicates any problems. In the rare occasion that the temperature probe stops working properly, the automatic shutdown feature will stop the connected equipment. (Product details: -No switchboard necessary -Ballast is always standby -Easy to install -2X the temperature safety features -Built in sunrise/sunset -Displays output in watts or % -Calibrate sensor).