explain: Rechargeable light sensing bicycle headlights; LED: 1x5050 high-power LED; Battery: 18650 rechargeable lithium battery; Brightness: 400Lm; Usage time: 3 hours in high light mode; Dimensions: 108 x 32 x 41 mm; Product features: Adopting high brightness 10W LED, with high brightness and long service life; Using high-quality 18650 lithium batteries, with a maximum of 1000 charges; Adopting a special algorithm constant current driving circuit to balance brightness and heat dissipation performance; Meets IP65 protection level and can adapt to various complex outdoor environments; Adopting high-quality lighting control chips and algorithms, it can automatically switch light sources based on environmental brightness; Multiple modes and brightness options are available. Lighting mode description: Button function: Click the button: Strong light ->Medium light ->Low light ->Close, and so on; Double click button: flashing (10Hz) ->slow flashing (2Hz) ->SOS, and so on Description of light sensing mode: The function of light sensing mode: When the lamp detects insufficient ambient light, it will automatically turn on the light source (the brightness of the light source is the brightness used in the previous light sensing mode); When the lamp detects sufficient ambient light, it will automatically turn off the light source.