... speaker for your convenience, connecting to your MP3,MP4, CD, DVD, GPS, PSP, mobile phone, notebook computer, ... 150-18000HZ(±3Db)l Signal and noise ratio of power amplifier: ≥80Dbl Loud speaker 1.77 inches ( ... 45mm) Magnetic resistant 4Ohmsl Power supply: 5V/1000Ma AC power adapter, computer USB power rotate connect line(optional)l ... it is so. More photos: Portable cd player with mini speakers-xkd3