... response: 150-18000HZ(+-3dB) Signal and Noise Ratio of Power amplifier: ≥80dB Loud speaker: 1.77inch(external diameter 45mm) ... perfectMini audio box with new concept integral stereo portable mobile music, connecting your MP3, CD, DVD, iPod, iPhone, GPS, PSP, mobile phone, notebook computer. High ... option. This compact travel speaker system is ideal for use at the office, home, carry where you go ...