APPLICABLE BATTERY: Supports 3-20 series lithium battery packs, 4-24 series lithium-iron phosphate 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 reinforced waterproof screen. It simultaneously displays battery voltage and remaining capacity, allowing users to clearly view the battery status. POWER-OFF MEMORY: After the voltmeter power is turned off, the function settings retain their previous state. LOW VOLTAGE ALARM: The low voltage alarm activates when battery power drops 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; in low-power mode, it is below 1mA. CALIBRATION: Includes a calibration screw hole for zero bias adjustment by turning the screw, enhancing accuracy and convenience. EASY TO INSTALL: The voltage meter can be easily mounted on a panel using the included nut and bracket. WATERPROOF & DUSTPROOF: Features an IP67 waterproof rating, providing protection against water splashes in most conditions. Color: Black Material: Plastic Package Contents: 1 x Battery Capacity Tester Note: Other items not included. Light reflection and differences in display screens may cause slight color variations between the image and the actual item. Measurement error allowance is +/- 1-3 cm.