In-wall cable

My home was built 65 years ago by do-it-yourself owners.  Lord knows what's inside these walls.  ☹

Thank you Mike! Excellent topic! I already contacted Jim who is real expert in this field but can not believe that wire I am looking for could not be made in this country..

In-wall 10awg wire generally should be solid.

I had stranded wire in old house and love it. One of the solutions would be Southwire MC Armorlite but in that case I would need metal wall box which I would like to avoid

I plan on upgrading several of my dedicated lines with this:

Kingrex In Wall Wire

Any reason you are looking at stranded wire instead of solid copper?  I believe Romex 10/2 (2 wire + ground) is the standard choice in this situation?  Will handle up to 20 amps.