4 in 1 Charger Socket Panel: This 12V socket panel is designed with 12V RV USB socket + LED digital display voltmeter + 12V cigarette lighter socket + LED rocker switch. Convenient to install and use. Also detachable to replace other charging sockets or anything suitable. Waterproof Dual USB Charging Socket: This 12V USB car socket has two built-in USB charging ports, two output ports: 5V/2.1A and 2.1A (total 4.2A), it will automatically detect your devices and charge 2 devices simultaneously at the optimal speed! Real-time LED voltmeter with a large digital voltmeter display. Displaying voltage of 5-48V, you can monitor your car or boat battery status if the voltage is in normal state. LED Rocker Switch for On and Off: Designed with flip style, easy to use. Long lifespan up to 10,000 cycles. An additional cigarette lighter socket is portable for other devices in your vehicle. Overload Protection: Overheating, overcurrent and overload protection; This dual USB charging socket is also