How to turn off H7 pen when not using

Hello, I just purchased a Chuwi Hi10 Max, as a set including its built in keyboard, Chuwi mouse and H7 pen.

I was able to successfully start using my tablet and also pair the H7 pen.

But I could not see any on/off button on the H7 pen. When I stop using it, how should I turn it off? I just want to make sure the H7 pen stops consuming its battery when I don’t use it.

I was looking for a use guide / specs document but I wasn’t able to find one.

Please advise me with my concern if you can. Thanks!