4 in 1 Design: This multi-function panel is designed with 12V USB socket + LED digital display voltmeter + 12V cigarette lighter socket + LED rocker switch. Convenient to install and use. Also detachable to replace other charger sockets or anything that fits. Waterproof Dual USB Charging Socket - This 12V USB charging socket has built-in dual USB charging ports, output two ports: 5V/2.1A and 2.1A (total 4.2A), will automatically detect your devices and simultaneously charge 2 devices at optimal speed. ! Real-time LED voltmeter with large digital display of the voltmeter shows 5-48V voltage, you can monitor your car or boat battery status whether the voltage is normal. LED ON/OFF Rocker Switch - Designed with rocker style, easy to use. Long lifespan up to 10,000 cycles. An extra cigarette lighter socket is portable for other devices in your vehicle. Overload Protection - Overheat, overcurrent and overload protection; This dual USB charger socket is also intelligent to identify the most