3-in-1 cigarette power strip - This 12 V power strip is equipped with a 12 V USB socket + a voltmeter with LED digital display and a 12 V cigarette lighter. Multifunctional 3-hole control panel for DIY needs, removable to replace other charging sockets or other parts. Convenient to install and use. Cigarette Lighter Junction Adapter - Extend the cigarette lighter connector so that you can use a variety of portable devices in your vehicle at the same time. Waterproof double USB charging socket - This 12 V USB car socket has two built-in USB charging ports, two output ports: 5 V / 1A and 2.1 A (total 3.1 A), it automatically detects your devices and charges 2 at the same time Devices at optimal speed Real Time LED Voltmeter - The large digital voltmeter display that shows a voltage of 5-48V allows you to monitor the condition of the battery in your car or boat when the voltage is normal. Overcharge Protection - Overheated Overcurrent Overcharge Protection; This dual USB charger socket is also smart to find the most suitable current for your device.