Nothing majorly wrong with this mute, but there are better alternatives out there (all be it more expensive). At first it kept falling out of the bell and would not feel secure, but after a few days of playing it, applying cork grease, wettening corks and trying out various techniques of putting the mute in, it did eventually sort itself out after about a week. WHEN USING FOR THE FIRST FEW TIMES, DO SO OVER A SOFT SURFACE E.G. BED, SOFA, PILE OF CUSHIONS. I didn't and as a result when it did fall out the first time I tried it, an small, but noticeable dent was created! Really good sound all over and would reccomed for a first Harmon mute