Good product, reputable brand and reasonable price. Used on B-flat clarion for prescription ringtones (150mm bell). You can play without problem in a closed room without being heard and without altering the sound and thus avoid any flying pots and other hostilities for oneself or one's instrument. However, I suspect the mute sometimes hides certain small wrong notes that would be more easily heard without the mute but this one should (in my opinion) be used for learning or (as in my case) after a prolonged stop. Excellent product for the beginner. Reception at woodbrass always perfect.