Mini voltmeter, used to monitor the battery status of your vehicle, with reverse connection protection function, and the circuit will not be burned. Waterproof, comes from environmentally friendly flame retardant materials, easy to use and install. Suitable for 12-24V car/boat/ship/vehicle/motorcycle/truck/ATV/UTV/camper/caravan/travel/trailer, etc. Twist lock system. Display : 3 digits, LED digital tube, LED display is green. Installed in the 1-1/8"" hole in the board, 0.25"" thick, a nylon mounting nut secures the meter in place. Specifications: Waterproof Measuring voltage: 6-30V Input voltage: DC12V-24V Dimensions: 1.4 inches x 1.4 inches x 0.5 inches Interface type: positive and negative Material: environmentally friendly plastic Scope of application: applicable to all vehicles at general purpose such as automobiles and motorcycles. Package includes: 1 x LED voltmeter 2 x isolation terminal