Ricco&reg; MD02 Computer Speaker (Silver) Latest SB Audio DSP (Digital signal processing) Technology, No more 3.5mm audio-in cable Compatible with Any Laptop/Desktop Computer with USB Port, PC and MAC compatible Computer OS: Windows (XP, Vista, 7), Mac OS X (10.4 or higher) Convenient Power Source: 5V USB Self Powered Very Light aluminium body, Total Weight only 250g. Dimension: 74mm50mmx53mm Powerful Output: 6W (RMS), S/N Ratio=79dB,Impedance:4 ohms, Frequency:80Hz-20kHz.