Most string trimmers without battery are part of the battery platform. For example, Bosch and Gardena have their own battery platform. If you have a battery at home that's part of the same battery platform and has the same voltage, you can also use it with the string trimmer you're looking at. Cordless string trimmers are suitable for medium-sized gardens. If your plans is to trim ticker and higher grasses, a model with a blade is more suitable. A model with wire is suitable if you want to trim the edges of your lawn.