APPLICABLE BATTERY: Supports: 1. 3-20 series lithium battery pack, 2. 4-24 series lithium-iron battery pack, 3. lead-acid battery of 12V, 24V, 36V, 48V, 60V, 72V, 84V. This product also supports custom mode in range of 9.5-100V. DISPLAY: The product uses digital display LCD with backlight, equipped with a strengthened waterproof screen, it displays both battery voltage and remain capacity simultaneously, enable users to view the state of battery clearly. POWER-OFF MEMORY: After cutting off the power supply of the voltmeter, the function setting will keep the state before power-off. LOW VOLTAGE ALARM: The low voltage alarm will work when battery power is less than 10% (battery icon flash). This reminds you that the battery needs to be charged. LOW POWER CONSUMPTION: The voltmeter has a very low power rate, at normal mode, its self-current consumption is below 15mA, while low-power-consumption working mode is below 1mA. CALIBRATION: A calibration screw hole allows to adjust the voltmeter to zero bias by simply twisting the screw for enhanced precision and convenience. EASY TO INSTALL: The voltage meter can be mount on panel or installation surface easily with nut and bracket included in the package. WATERPROOF & DUSTPROOF: The voltage meter features a waterproof level of IP67, which means it can resist water splash in most situation. Colour:Black Material:plastic Package Contents: 4 x battery capacity tester