Set the desired draw off temperature with the up/down arrows. When the syrup temperature rises above the draw off temperature, the solenoid valve opens, letting the syrup out. When the syrup temperature falls below the draw off temperature, the valve closes. Check the syrup density with a syrup hydrometer as it draws off and adjust as necessary. It’s a real time saver, it’s like having another person in the sugar house helping out. Includes the controller, temperature probe and solenoid valve.