Key benefits Realtime battery monitoring while charging: The USB charging socket includes an LED voltage display, letting you see the car battery voltage in real time to help prevent safety issues caused by battery failure. Clear status indication: Voltmeter indicator lights show in blue and red for quick ataglance status. Safe, reliable charging: Builtin multiple protections guard against input and output faults, reducing the risk of damage to your vehicle electronics and peripherals. Durable, weather resistant design: ABS housing with a waterproof USB cover protects the module and its circuitry in wet or dusty conditions, extending service life. Specifications Voltmeter indicator light color: blue and red. Monitoring range: DC 630V. Input voltage: DC 12V. USB output: 5V / 3.4A, 9V / 2.5A, 12V / 2A. Digital LED display Integrated LED voltage display on the USB charging socket shows the vehicle battery voltage in real time, helping you monitor battery health and avoid batteryrelated safety issues during use. Protections Input protection: overvoltage and undervoltage protection. Output protection: overcurrent, overvoltage, undervoltage, and short circuit protection. Additional protection: reverse connection protection. Thermal protection: temperature protection inside the chip. Waterproof and durable construction USB waterproof cover provides waterproof and dustproof protection even in rainy conditions, safeguarding the internal circuit. Shell material: ABS plastic, designed to be strong and durable to extend service life. Use scenarios Invehicle charging and monitoring: connect to a 12V car system to charge devices via USB while continuously monitoring the battery voltage to prevent unexpected battery failure during daily driving. Outdoor and travel applications: suitable for use in trucks, RVs, boats, or other 12V systems where you need USB charging and battery status visibility in challenging weather. Workshop or emergency use: provides USB charging for mobile devices from a 12V supply while keeping an eye on battery voltage to avoid electrical issues in a garage or roadside emergency setting.