Crescendo Vocals Musicians Ear Plugs (NRR 10)PeterMay 9, 2013I sing in a classical choir and was having a hard time hearing myself through the loud tone of the guy next to me. I couldn't hit the right pitches through his missed notes and caught myself closing (w finger) the ear on his side at critical parts. You can't do that in a concert. I got these plugs and put one plug in on his side and kept the other ear open and I did much better. If I had been between 2 loud singers I could have gotten along w both plugs but didn't need to. The valves allow your ears to equalize pressure. You don't get that smothering feeling. It's great that they provide you with 4 plugs: 2 medium and 2 large. The mediums fit better for me. No one ever noticed or commented on the plug.