... option usb power supply Great sound effect and high price 2.0 speaker Features:1.Appearance: elegant and simple2.Different color choice ... ,, mp3,mp4,CD,mobile phone. Technique Parameters:Output power:2.5W*2Loudspeaker specification: 2 8Ω 8W full rangeFrequence response: 90Hz - 20KHzSensitivity: 80db ...