Skull Candy is one of the more popular mid-grade manufacturers of headphones and audio enhancement products. Some of their headphones are worth every penny you pay for them and others are a waste. I wish I would have know about the poor sound quality on these before I purchased them. While they are comfortable to wear, the sound is borderline horrid. Even when I adjusted the equalizer on my MP3 player and turned on the bass boost, the music I was listening to sounded faded and weak. The only thing that I use these for now is listening to sports broadcasts, audio books and spoken word performances. Anything with music is going to sound like you are listening to it in a tunnel. I did get these on sale so it wasn't that bad but if I would have paid full price for them I would have taken them back for a refund or an exchange. If all you need is a standby pair or something to listen to the news or weather then these will work but for music, spend a little more and get one of the nicer pairs of headphones. Sound Quality Horrible for music. Performance For music, these get low marks. For sports broadcasts and lectures, they are worth it. Battery Life No batteries needed.