Features 1.With waterproof design suitable for indoor/outdoor or ocean use. 2.Built-in overload over-current and short circuit protection very safe to use. 3.UV stabilized nylon housing with rubber splash-proof & tight-fitting front cap. 4.Voltmeter with three digit LED digital display real time monitor the battery voltage. 5.Mounting screw and labels included easy to install can be installed horizontally or vertically. Specification Features:With waterproof design suitable for indoor/outdoor or ocean use. Built-in overload over-current and short circuit protection very safe to use. UV stabilized nylon housing with rubber splash-proof & tight-fitting front cap. 2 pole nickel plated brass terminal connectors Mounting screw and labels included easy to install can be installed horizontally or vertically. Use on automotive electronic field electrical devices most car truck buses SUV home boat camper/RV ATV UTV golf cart and more electrical devices. Can be used to charge for mobile phones tablet GPS digital cameras PDAs etc. Specification:Material: Nylon Item Color: BlackLED Color: GreenUSB Output Current: 3.1A2.1A/1A)Interface: 2 USB Voltmeter Display Range: 0-35V DC 10AVoltmeter Mounting Hole: 29mmSize: Shown as Picture Package Weight: approx.355g/12.5ozFitment: universal for 12-24V car boat marine RV truck and etc.Package list:1 * USB Charger with Voltmeter(As picture shown)3 * Cables9 * Blue Terminals 4 * Screws Package List