The LiPo batteries usually have two connectors, the main connector and the balance connector:

Provides the main power for the battery when charging and drains the power when discharging. It is directly connected to the electronics.

WARNING: Some small batteries have two main connectors, one of them can be confused with a balance connector and produce a short-circuit to the charger (white connector in the picture).

This cable is plugged into a battery charger and provides the information needed to keep the voltages between cells almost equal.

This number indicates the total of cells that a battery has.

The nominal voltage of 1 cell should be 3.7V. It can go up to 4.2V and as low as 3V, but they should never exceed this limits.

Is the amount of energy that the battery can store, measured in miliamps hours (mAh). With a 1000mAh battery, the energy will last 1 hour with a continuous draw of 1A or 1000mA.

This number is usually followed by a “C” in the battery package. It indicates the maximum rating at which a battery can be charged or discharged. With a 1000mAh battery and 2C, the maximum current you can pull is (2*1000mAh) = 2000mAh without damaging it and it will last half the time. In the other hand, the maximum charge current is (2*1000mAh) = 2000mAh and it will be charged in half the time.