I purchased this backtrack .5 to use on a camping trip to see how far we were from our camp when we went hiking. It did exactly what it said it would. It got me back to camp and was generally accurate. They tell you it has to be "calibrated" every so often when you turn it on, and yes it did. If you didn't, it told you you were going the wrong way and I know i wasn't. Flip it around a few times to make sure it locks on to additional sattellites and it was 100% dead on. Was very helpful to know we were over 2 miles from camp. The back piece was a little difficult to get off without breaking the little piece of plastic, just make sure you have it straight up and down. Batteries lasted most of the weekend. I used lithiums and used it for 2 days so I would say b+ on battery life.