[felixhandte]

They don't actually turn off though. It just turns the display off. They need to continuously sense position since digital calipers measure movement increments rather than absolute position. That's why if you take the battery out and put it back in it will prompt you to re-zero the calipers.

Amusing video explanation: https://www.youtube.com/watch?v=KnDype-j3hk

[maxerickson]

It's not uncommon for them to be designed to require zeroing at each power on.