Mp3 player 1.This player can work without any external speakers, so it is portable. 2.This player has ternary jack for charging, data exchange & built-in power switch 3.Music format: mp1 / mp2 / mp3 / wma / wav / asf / wmv 4.Port mode: usb 2.0 5.Eq mode: pop / classic / soft / jazz / dbb / rock / normal 6.Playing time: continuously playing time for 350-400 minutes after fully charged 7.Battery voltage: 3.7 v rechargeable li battery 8.Output power : 55mw 9.Headphone output power: 5mw 10.Requency response: 20hz-20khz 11.Battery charge time : about 3 hours 12.Working current: 35-40 ma 13.Info/ noise ratio: 86db 14: color: silver 15: this product 's main body is headphone, and built-in mp3 and li battery. Pls email to me for more.