It used optical switch design and will automatically turn on in dim or dark environment and automatically turn off in bright environment. It really saves energy and lasts longer time. - It used body sensor and the sensor angle is 90° sensor range is 5m. 3 LEDs turn on when people in sensor range and after people leave the sensor range it will get into energy-saving mode and keep 1 LED light. - Built-in LiFePO4 battery can resistant in 80'C environment and has longer working life than others. - It suits for courtyard garden outer wall corridor balcony and so on.