auto taps

I am looking for a shower tap that turns off after a while to conserve water.  I know I can just turn things off, but others have an issue with the idea. I've seen them for a kitchen or bathroom sink but not for the shower. I haul water and every drop is precious. Does anyone use such an item? sources?

There are all kinds of timed shower valves out there here is a simple shower head one. https://www.showermanager.com/
There are actual valves some electric some not.