This is a single unit of 12.8V-42ah (42000mAh) Lithium Ferrous Phosphate Battery with inbuilt Battery Management System (BMS) which provides it multiple protections as well as ensures enhanced battery performance & life. This type of battery is suitable for Off Grid Lighting, Solar Kits & Streetlights as well as for General Lighting. One may use it like any other battery but with the advantage of having a lithium type battery which is portable, durable, easier to install & handle as well as more efficient. It can be charged via 12V solar panels of 50W & above with a charge controller in between. By purchasing charge controller or regulators, one can use it for off grid purposes while trekking, camping or otherwise. If used efficiently & properly, it will deliver upto 1500 cycles during its lifetime.