Usage: Connected the display panel positive and negative terminals to the tested battery positive and negative side, then the digital tube will show the battery levelbattery capacity display parameter:Battery voltage >11.2V, 1 Grid LightBattery voltage >12V, 2 Grids LightBattery voltage >12.5V, 3 Grids LightBattery voltage >13.3V, 4 Grids Lightwhen battery voltage <11.2V ,the 4 grids all off,it means you need to charge the battery right now Features:With a shell, easy to use stand-alone or embedded in the panel on the product.Display Mode: Battery +PercentageBlack wire connect negative electrodeRed wire connect positive