Feature: USB Car Charger: 1. Support for all operating voltage 12V-24V machine motive or electrical equipment to use, to any smartphone, tablet charging, fast charging. 2. 2 hole USB charging socket supports a variety of electronic products, with LED blue lights, have passed CE certification, with positive and negative reverse protection. 3. Cover with a waterproof, dustproof and waterproof good effect. Voltmeter: Voltmeter range DC 6-30V, has reverse polarity protection function, line reversal will not burn. For monitoring the battery voltage, battery voltage state to grasp, it can also be used for other products voltage measurement purposes. Ammeter: Ammeter measurable range: 1-10A, having a reverse protection function, line reversal will not burn. For detecting device current. Specification: Material: Environmental pollution with a new nylon material, Voltmeter Display color: Red. Ammeter Display color: Red. Ammeter range can be measured: 1-10A. Voltmeter range can be measured: 6-30V. UBS Output voltage: 5V. USB Maximum output current: 3.1A. Weight: 100g. Installation method: The product placed in a fixed panel of the General Standard nut tightened Then can be fixed with screws. Package Included: 1xCar Charger