I liked the idea of this caliper, but unfortunately I can't recommend it in practice. It takes a surprising amount of light to function properly. And when you take it out of the case, there's no charge. So if you're measuring something and accidentally direct it away from a light source, it dies. It does not have an auto power off function. So if you put it in a suitcase, it dies. Also, you can't expose it to sunlight, otherwise it will damage the batteries. Therefore, it cannot be used…