Portable 2.0 Mini USB Digital Speaker [D-015] Portable Speakers Easy to Carry Everywhere ​ System Configuration USB 2.0 & USB 1.1 With Audio Output With Sound Card Supports Hot Plug & Play Specification Speakers Dimension & Impedence: 4-OHMS Output: 5W Frequency: 90Hz-20KHz Sensitivity: ≥ 80dB Distortion: ≤ 0.3%