12 in 1 Controller: This 2 in 1 pH and ORP controller and monitor simultaneously measures and displays pH and redox (ORP). 22 BNC Electrodes: It comes with 2 BNC electrodes (pH and redox) and 2 output power sockets, both electrodes are removable and can be easily replaced at any time. 3Relay Output Power Socket: As for the relay output power sockets, you can plug in your own 110V or 220V devices, such as vent stones, O3 ozone generators, oxygen pumps, CO2 regulators, solenoid valves and other ORP and pH control devices. 4How It Works: If the currently measured pH or redox value is lower than your set value, it will turn on your device, if the measurement is higher than your set value, it will turn off your device. 5Simple to Use: This digital redox controller uses simply, just need to set the desired high or low pH or redox value in the controller.