APPLICABLE BATTERY: Supports 3-20 series lithium battery packs, 4-24 series lithium-iron battery packs, and lead-acid batteries of 12V, 24V, 36V, 48V, 60V, 72V, and 84V. This product also supports a custom mode within the range of 9.5-100V. DISPLAY: The product features a digital LCD display with backlight and a strengthened waterproof screen. It displays battery voltage and remaining capacity simultaneously, allowing users to clearly view the battery status. POWER-OFF MEMORY: After power is disconnected, the voltmeter retains the previous function settings. LOW VOLTAGE ALARM: The low voltage alarm activates when battery power is below 10% (indicated by flashing). This alerts the user that the battery needs charging. LOW POWER CONSUMPTION: The voltmeter has very low power consumption. In normal mode, self-current consumption is below 15mA, and in low-power mode, it is below 1mA. CALIBRATION: A calibration screw allows adjustment of the voltmeter to zero bias by turning the screw, enhancing precision and ease of use. EASY TO INSTALL: The voltage meter can be easily mounted on a panel using the included nut and bracket. WATERPROOF & DUSTPROOF: The voltage meter has an IP67 rating, meaning it is protected against dust and water splashes in most conditions. Color: Black Material: Plastic Package Contents: 1 x Battery Capacity Tester Note: Light reflection and differences in display screens may cause slight variations between the color of the item in the image and the actual product. Measurement error allowance is +/- 1-3 cm.