It also does ballistics for bullets too. It is super compact and easy to set up. Those two features alone make it worth it to shop owners or people who shoot a lot or develop custom loads or arrows. Instead of having to set up the Caldwell on the tripod and get it all out of the bag, you pull this thing out, turn it on and shoot over it and you're done. If you only shoot once or twice here and there, this is overkill. But if you are constantly testing new arrows or bullets. This is way nicer than the Caldwell or Magneto Speed.