Note: Before first use, please charge it first, then you can use it normally after activation. It is recommended to use it again after fully charged. Function:● Tail light/brake light/anti-theft alarm/bike bell 4 in 1 function!● Reminding surrounding pedestrians and drivers with light and sound warning, effectively protect the safety of car and rider!● The warning light will turn on automatically when passing through the tunnel or when night driving!● The brake light will be illuminated immediately after braking or slowing down!● Armed when parking, deterring thieves and effectively protecting your car with loud sound and blink alarm!● PC + anti-UV material, waterproof and dustproof, resistant to high and low temperature , not afraid of wind, rain and severe cold and heat! Product:1. Storage temperature: -40 ~ + 70 ℃2. Working environment humidity: 80%3. Ambient temperature during operation: -40 ~ + 70 ℃4. Alarm charging port: standard USB-C 5V Type C (Some fast chargers may not be compatible)5. Alarm battery: 3.7V 700mAh lithium battery, working time about 1-3 months, standby time about 6 months.6. Remote battery: WLO3C: 27A(12V) alkaline battery, working time about 1-2 years (5 times a day). Low battery warning and charging: 1. Check if the remote control indicator can light up. If not or the light is weak, please replace the remote control battery.2. The alarm is in low power mode when received. In this mode, the remote control cannot control the alarm. Please charge the alarm at least 1 minute to activate before use, otherwise the remote control cannot control the alarm.3. If the alarm has been charged and activated, the remote control still does not work, please re-pair the remote control and alarm. Evaporation method see.