... and More.With special particular patent in worldwide. Be applicable for MP3, MP4, laptop, PC, MD, mobile phone, and more With ... /N: 80dB AMP frequency range: 280-16KHz Charge voltage: 5V +0.5V Suitable temperature: 0 - 40 C Be applicable for MP3, MP4, laptop ... will be expanded while playing, that will increase the low frequency outputting If power off, close the resonator, the dimension will ...