dose not work.
slider can move but sound is not changing at all.

doesn't work in youtube

Good interface and options. Sometimes the options get a little too technical.

However, the main reason for 2 stars is that it didn't work on Firefox 68.0.1 (64-bit), on music.amazon.com I haven't tested in other sites.

Funktioniert NICHT !!!

не меняет звук вообще