1. Always keep the battery on fill voltage condition. 2. Prevent the battery from over-charging. 3. Prevent the battery from over-discharging. 4. Prevent the battery from reverse charging to solar panels during nights. 5. Reverse Polarity Protection for Battery 6. Reverse Polarity Protection for Solar Panels 7. When the battery voltage is low, the controller will automatically cut off the load from the system. If the voltage of battery is back to normal and the load will restart working. 8. Thunder protection 9. According to the battery voltage grade, the controller can automatically set charge-off voltage, the load-off voltage, the load- voltage. (The parameter is default under 25 condition, locked by the CPU procedure, cannot adjust.) 10. The controller will automatically compensate the temperature of the charging voltage according to the changes of temperature. Colour:blue :ABS type:30A Package Contents: 1 x Solar Panels Battery Charge Controller 1 x Chinese and English manual 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 a little different from the real thing. The measurement allowed error is +/- 1-3cm.