It could be a 18650 or another lithium standard size and make everybody Happy. Easy to remplace and a bigger life than square sized batteries.

My thesis advisor gave me that book at the beginning of my PhD. One of his few good pieces of advice during the thesis.

You can check the cables that comes from the button and short them, it should make the bell ring.

Start by measuring the voltage and try one that reduces to half of it

As a researcher I always make sure that there is at least a preprint available for download, and always try to publish my research in open access journals (which is much more expensive).

I will be glad if someone pirate my papers, it is a corrupt system in many ways.

I couldn’t use Tor inside China, I tried but did not establish a connection. Didn’t dig into it also.

I travelled to China in October 2023. I have a Wireshark VPN running at home with my internet provider (dinamic IP), and it worked for few hours (about 6) and they ban the IP. Resetting the router and getting a new made it work for another few hours.

As others suggested the vpn traffic is encrypted but very easy to detect. I read about some protocols that can bypass it like shadow shocks but I didn’t have time to tinkering (it was my first time in China).

I ended by using the service provided by 12vpx and it worked flawlessly. Someone recommended it and it is specialized in provided access in china with lots of gateways. I never had problems with this provider.

Probably there are others that also work but that is my experience.