Description: The black wire is connected to the negative battery and the red is connected to the positive battery. Dual display power + voltage, at a glance, the display is more intuitive. The upward 8 color bars show the battery power and the downstream voltage meter (display battery voltage), and the voltmeter decimal point automatic accuracy is higher. It can be used in a wide range of applications, such as 18650 lithium-ion polymer lithium battery packs, -acid batteries, electric vehicle batteries, and nickel-metal hydride batteries. Easy to install and easy to disassemble. Specification: Material: Plastic Size: 48x28x22 mm / 1.88x1.10x0.86 inch Measuring Range: 6-100 (V) Input Voltage: 6-100 (V) Output Voltage: 6-100 (V) Ambient Temperature: -10 ° C ~ +65 ° C Package Includes: 1 Piece Battery Voltage Tester Note: The positive and negative terminals of the display panel will be connected to the positive and negative terminals of the battery under test. The digital tube will display the real-time battery power (do not reverse the positive and negative poles, otherwise it will be directly damaged)