Many cordless tools are part of a battery platform. For example, Makita, Bosch, and DeWalt battery tools have their own battery platform. The advantage of this is that the batteries are interchangeable. This means that you also use the same battery for other (garden) tools of the same brand with the same voltage. Do you already have a battery at home that belongs to a specific battery platform? You don't have to purchase an extra battery when buying new tools.