SQDeal 12V Universal Cigarette Lighter Socket + Dual USB Power Adapter Charger + LED Digital Voltmeter for Car Auto Motorcycle Boat Riding Mower Tractor Travel Trailer Caravan (3 in 1) LED Voltmeter monitors your car and ensures its normal work. Dual ports allow charging 2 USB devices simultaneously. Supplying power for your MP3, GPS, camera etc any time. Waterproof, dustproof material can be used for the interior and exterior application. Short circuit, overheat protection design for safe to use. Portable design, easy to install, function port can be detached and rearrange. It can be installed vertically, horizontally, underneath the dash, or any flat surface. Fastened with 4 screws and 6 insulated terminals (supplied).