All Brass sound intensifier ring for Trumpet

Bell sound intensifier ring. It is a silver plated bronze ring, with a cut that allows to introduce it through the thinnest part of the bell (near the machine) and wearing it, it fits over the bell at the height where the mark of the instrument is normally engraved. It is fixed in place due to the excellent quality of the cork inside. 
The effect it produces is to centre the sound on each note. Ideal for filling work, chamber music or similar. Very good also when you need to amalgamate the colour of a valve trumpet with a rotary system trumpet.