V-mount chargers are used to charge V-mount batteries, often also serve as mains power and of course smart microprocessor friendly charging. The chargers also come with 4 slots for charging up to four V-mount batteries. You'll normally encounter a 4-pin XLR power output that can be used to power the camera. For multi-battery chargers, there is usually an integrated handle to make it easier to transport the charger with the batteries attached.