AC-3 5.1-Channel 2.4G Wireless Surround Sound Speakers with LCD Display Subwoofer: Drive Unit : 6 Inches Output Power:50W(RMS) Frequency:38Hz-250Hz Impedance:8 Ohms Sensitivity:85dB THD<0.1% Full Remote Control Tower Speakers: Drive Unit: Front:2.75 inches *3 Center:2.75 inches *3 Surround:2.75 inches*3 (wireless) Output Power:20W(RMS)*5 Frequency:250Hz-20Khz Impedance:8Ohms Sensitivity:85dB Tower Speakers made of Plastic