5.1-channel amplifier Real 5.1-channel input/output, 1 AUX input Highly magnetically shielded All-function remote control VFD display Tower speaker: Drive unit: 2 inches x 4 Frequency:250Hz-20kHz Sensitivity: 87dB Impendance: 8 ohms Power: 20W Subwoofer: Drive unit: 6.5 inches Frequency:38Hz-250Hz Sensitivity: 87dB Impedance: 8 ohms Power: 40W THD< 1% decoder or FM radio (optional)