1.*Work with all 3.5 audio interface devices : MP3 , 2.for smartphone, smart pad *Chargeable, Enviroment protection. INTRODUCTION We, Ko- ... plug ,connects to Ipod,Iphone,Mp3 and most audio devices 2) built-in lithium polymer battery ,recharge through standard USB port3 ... indicate power status4) Frequency range:90Hz - 20 kHz 5) Output :2 X 2 W6) distortion: 0.3% 1W 1KHz7) Signal to noise ratio ...