it seems to be optimized for dry walls. not sure how it would perform on concrete or other stone walls. Also I could not find a technical description how it works.

It uses the 60ghz radar from https://vayyar.com/ . I'm not sure how or if it works, I haven't tried it myself. They also sell dev kits: https://walabot.com/products/walabot-developer-pack-new

Have you tried this product? What do you think of it?

I have, it works ok, but I still use a regular stud finder most of the time, unless something bizarre is going on.

It has been useful to find pipes and electrical with some confidence, when their location is called for.

There are slightly nicer stud finders that use magnetics to detect live wires.