STROMTANK S-1000 review from professional recording studio TheSoundphile. 

I’d like to know who changes the batteries in twelve years and what it costs when in I’m 75 years old and can lift it or bend down.

Where can I find the original files for a comparison?

wow

👍

It's not worth watching the video since I know this guy is going to claim he heard something. But he didn't. Devices like this have been tested and tested by sites like audio science review, and there is no benefit to having them.