WIDELY USED: Widely used for DC 9-24V car, truck, Motorcycle, RV, ATV, boat, Camper Vehicles, etc4 IN 1 DESIGN: This four-hole panel includes 2 USB charger socket (Output: DC 5V/4.2A) + LED voltmeter (Display range: 6-24V) + 12V power outlet (Output: DC 12V) + ON-OFF Toggle Switch, they are interchangeable. You also can replace any port with additional USB outlets, or anything else that fitsWIDE COMPATIBILITY: The USB socket port fits for charging HTC, Galaxy, Blackberry, MP3 Players, Digital Cameras, PDAs, and Mobile Phones. LED digital display looks cool, especially in darkDUAL 12V USB CHARGER OUTLET: The LED voltmeter shows 9-24V voltage when driving which can remind you whether the voltage is at a normal level, ensure driving safety. The cigarette lighter socket Works with any standard cigarette lighter plug or lockable marine plugSAFETY PROTECTION: CE & ROHS certified, display the current detected by the intelligent circuitry while charging. Intelligent circuit design protects aga