Its lithium ion/Lead-acid/Lithium phosphet batteries charger capacity meter. This meter can work precisely for any of three battery category. It shows both voltage and capacity in 0 to 100% form.
With the switch on the meter its  easy to install and use, no need for external control switch;
The front is a PVC film, the surface can be waterproof;
Liquid crystal display, power saving, saving more than 50% power over conventional power
The following battery is universal
Lithium ion battery: 3s to 20s
Lithium phosphet battery - 4s to 23s
Lead acid: 12V 24V 36V 48V 60V 72V 84V
 
Specifications:
Operating current: <5mA
Display mode: LCD percentage% / voltage
Color: Green
Waterproof grade: surface waterproof
About installation
Installation method: shell with snap-lock (without screws)
Product Size: 61.3*33.3*13.5mm
Embedded size: 58.5*28.5mm
Package includes:
1 * 12V-84V Lead-acid Battery Capacity Voltage Indicator
1 * Cable