All batteries are composed of cells assembled in rows. The starting point of a battery is it’s cell. For an NiMh, the cell is always rated at 1.2 volts per cell and for a LiPo it’s starts at 3.7 volt. A battery is composed of two characteristics: The voltage and the amperage. The higher the voltage, the faster the motor will turn, therefor the harder the gun will shoot. But be careful, A battery that is too high of a voltage could damage the piston and the components of your gearbox.