With a string trimmer with a battery, you have complete freedom of movement. You're not tied to extension cords and you don't have to worry whether there's a socket nearby. This makes it suitable for medium-sized gardens. If you're planning on trimming higher and more stubborn grass, a model with blade is suitable. A model with wire is useful to trim the edges of your lawn. Most trimmers that work on a battery are part of a battery platform. If you have a battery at home that belongs to the same battery platform with the same voltage, you can also use it on your string trimmer.