The extension I used to use for a volume booster has been banned by Mozilla so whilst I was looking for another addon, I came across this. I have to say the UI looks very clean and modern whilst some of the others look dated. The presets and the scroll wheel make my life so much easier. The bit I like the most is that the sound settings I choose are saved per website, so If I wanted 200% on youtube, but 150% on twitch, I wouldn't need to keep changing it, It stores my selection for me. I would highly recommend!