I just bought some a couple of weeks ago. So far my conclusion, sadly, is that they are bollocks.
They significantly alter my hearing, but just in a similar way to sticking my fingers in my ears, and have no discernible effect on my tinnitus.
I am disappoint.
I will persist and try to establish whether I am fitting them correctly etc. I would love them to be excellent, but no joy so far. Has to be said, I have quite irregular ear canals, and these are a generic fit, so that could be making a difference. Also hair in ears could be compromising the seal.