The external battery for certain Segway scooters makes the difference between worrying if you can make a trip and just going the distance. Now that I have this external battery I just go. I don’t worry about how far it is, I just plan my route. It only weighs 8 pounds so it doesn’t add that much ch weight. With the update on the app shows how much both batteries have. Another bonus is you can charge your phone or any device you may have with you!