— includes two replaceable batteries. The most obvious advantage of this configuration is the increased battery life: when the charge is exhausted, it is enough to change the dead battery for a fresh one. However, in addition to this, this option provides other advantages. So, it allows you to reduce interruptions for charging: one of the batteries can be charged at a time when the second is used for work. In addition, even if one battery fails, the second will remain operational; and the probability of simultaneous failure of both batteries is extremely low (and definitely lower than that of a single battery). On the other hand, you will have to pay extra for a second power source — although often its cost is less than if a spare battery was purchased separately.
