The Humes & Berg New Stone Lined ST-153 (where the "new" is ironic, since this mute has been around for many decades) is a legend in the trombone world. It produces a beautiful, lyric sound eternized by Tommy Dorsey's recording of Song of India. Actually, the sound of the mute is big, much larger than it sounds in Dorsey's recording. The only "criticism" is the sloppy finishing of the mute, but that is part of the Humes & Berg style, to make it look more artisanal. A good thing about Humes & Berg mutes is that they are made of vulcanized fibre, so that they don't dent as metallic mutes, when accidentally fall on the floor.