4 in 1 Design: This multifunctional panel is designed with 12V USB socket + LED digital display voltmeter + 12V cigarette lighter socket + LED rocker switch. Easy to install and use. Also removable to replace with other charger socket or anything else that fits. Waterproof Dual USB Charging Socket: This 12V USB charging socket has built-in dual USB charging ports, outputting two ports: 5V/2.1A and 2.1A (total 4.2A), will automatically detect your device and charge 2 at the same time. the best speed Charge your device! Real-time LED Voltmeter: With a large digital voltmeter screen that displays 5-48V voltage, you can monitor the battery status of your car or boat whether the voltage is in normal status. LED Rocker Switch: Rocker design, easy to use. Long service life up to 10,000 cycles. An additional cigarette lighter socket allows easy connection to other devices in the car. Overload Protection: Overheating, overcurrent and overload protection; this dual USB charger socket can also