Harmonics 216 high fidelity wireless stereo headphones with a decent bass and mid-frequency response. Music is food of the soul. Surround yourselves in incredible audio experience weather you are on a long trip or out for a morning jog or you are simply laying around on YouTube or Netflix on a relaxed weekend. The headset has an in-line mic and +/- control buttons. Except volume control, the + and - button can make it play next and previous, perfect for answering calls or listening. Compatible with almost all smartphones and other devices, including IOS, Android device, MP3 and MP4 music players, etc. Upgraded built-in lithium batteries support up to 6-7 hours talk / music time with battery indicator on IOS and Android (depends on volume and audio content) for prolonging enjoyment. Symmetrical balance and Ergonomics design ensure a comfortable fit.