The item is a DC4-30V 0-10A accurate micro LED digital Voltmeter board module. It is a good tool for you to detect and display Voltmeter. Features - Display Color: Blue - Cable length: 19 cm - Dimensions: 3.50X1.40X1.00cm/1.38X0.55X0.39in - Measuring range: DC 0 - 10 A - Supply range: 4 - 30 V - Dimensions: 35 * 18 * 9 mm - Cable length: 19 cm - Measuring range: DC 0 - 10 A - Supply range: 4 - 30 V - Equipped with no shell - Electric wire: Power input: Thick white wire Voltmeter output: Thick black cable Supply positive pole: Red wire Supply negative pole: Black cable Note - The measuring instrument is operated from the measured circuit, so : His thick black cable is the wire The thick white cable should be connected with the input of the Strengthening circuit. - The thick cable not allowed to be connected to the positive terminal of the device, otherwise seem any scratching or error, you just have to connect to the negative terminal - Please do not use a power adapter of poor quality - Connection cable between Voltmeter meter should not be too long, otherwise you need shielded cable Package list: 2 x Accurate Micro LED Digital Voltmeter Board Module DC4-30V 0-10A Voltmeter Monitor Voltmeter Display Panel Meter (White Letter)