Gewa Wolf Eliminator Cello

I am satisfied with this wolf eliminator, but it has a little problem for me:
I used it on a contralto nyckelharpa, I have to say that in my experience with this Gewa folf eliminator it's been not too easy to close it and fix it properly to eliminate the wolf. (But finally I did it!).
So I don't like too much the fact that it's difficult to fix it and avoid that it hits the bridge moving on the string, but surely, finally it works!

The screw which is used to fasten the tube to one of your strings isn't the best one ever. A few forte strokes on an open C string and it just resonates out of its socket, falling on your cello and damaging the varnish. I seem to be the only one who had this problem though, even though I tried multiple of them. I've heard good stories of other people using this one though.