Where can i buy backup battery for Homebase?

I live in France, impossible to buy the battery pack for the homebase. On Amazon, unavailable. How to do ?

You can buy the Eaton 3S mini, this one works with 12V, is from a reputable brand and should keep the homebase up for about 2-4 hours if I’m correct.

Wouldn’t you just buy a ups ? Keep your router active also ?