Spark-free Protection. Reverse polarity solar and battery connection. Reverse current from battery to solar panel protection at night Over temperature protection with derating charging current Transient overvoltage protecrion at solar input and battery output protects against surge voltage System Voltage: 12V Max Charging Power: 300W Max volt on Bat. Terminal: 25V Max volton PVTerminal: 40V Temp. Compensation: -4.17mV/K per cell (Boost, Equalization), -3.33mV/K per cell (Float) Dimensions: 144 x104x28mm Weight: 230g Grounding: Common Negative Mounting: Vertical Wall Mounting Maximum Terminals Wire Size: 11AWG(4mm2) Terminals Screw Torque: 1.47N-m Ambient temperature: -20- +55X Storage temperature: -25 ~ +80C Protection degree: IP65 Max Altitude: 4000m Colour:As shown Material:ABS Package Contents: 1 x Solar Controller 1 x Cable 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.