APPLICABLE BATTERY: Compatible with: 1. 3-20 series lithium battery pack, 2. 4-24 series lithium-iron battery pack, 3. lead-acid batteries of 12V, 24V, 36V, 48V, 60V, 72V, 84V. This product also supports custom mode in the range of 9.5-100V. DISPLAY: The product features a digital LCD display with backlight, equipped with a reinforced waterproof screen, displaying both battery voltage and remaining capacity simultaneously, allowing users to clearly view the battery status. POWER-OFF MEMORY: After the power supply of the voltmeter is turned off, the function settings remain as they were before power-off. LOW VOLTAGE ALARM: The low voltage alarm activates when the battery power drops below 10% (the battery flashes). This alerts you that the battery needs attention. LOW POWER CONSUMPTION: The voltmeter operates with very low power consumption; in normal mode, its self-current consumption is below 15mA, while in low-power-working mode it is below 1mA. CALIBRATION: A calibration screw hole allows for zero bias adjustment of the voltmeter by simply turning the screw for improved precision and convenience. EASY TO INSTALL: The voltage meter can be easily mounted on a panel with the nuts and brackets included in the package. WATERPROOF & DUSTPROOF: The voltage meter has a waterproof level of IP67, meaning it can withstand water splashes in most situations. Colour: Black Material: Plastic Package Contents: 1 x battery capacity tester Only the above package content is included; other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture to differ slightly from the actual product. The allowed measurement error is +/- 1-3cm.