After reading customer reviews of these earphones, I decided to buy them because of the noise-cancellation feature. Not all ears are created alike, so the Shures come with a variety of sleeves so that you can find your perfect fit. I also noticed that lots of people mentioned that there wasn't enough bass, but I usually find other earphones too bassy which makes the sound a bit muddy. The sound of these earphones is great! The only problem I had was that it blocked out the noise so well that I almost missed my train stop until someone gave me a nudge. They did come in handy one day when I was on the train and NINE kids got on and sat all around me. I popped in the Shures and closed my eyes and it was like they weren't even there!