1. The products are used in solar water heater, the temperature difference and temperature to control the output. 2. It is provided with two output control, temperature difference control two temperature zone. 3. When the temperature reaches the set value, it automatically runs the water pump circulation and makes the two temperature zone temperature equilibrium. 4. The other channel controls electric heating, when the solar heating failed to the set temperature, the electric heating system can automatically start and heat to the set temperature. 5. It will control heating system and automatically makes water temperature stay in temperature deference range. Working Voltage:AC220V 10%(50Hz/60Hz) Output Load:5A/220V/AC Power Consumption:less than equal 3W Heating Control Range:2-99 Temp.Difference Start Control:3-50 Resolution:1 Input Signal:2-channel sensor, 20KX2MX2 Operating Temperature:-10-50 Operating Humidity:RH less than equal 90% Colour:Black Material:Plastic Size:76x76x35mm/2.99x2.99x1.37in Package Contents: 1 x Temperature Controller 2 x Sensor Probes Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.