AN-2107 2.1ch Multimedia Speaker Systems---Standalone Amplifier Specifications: Output Power(RMS): Subwoofer25W; Satellites 10W*2 Speaker Driver: Subwoofer 6.5"; Satellites (3"+1")*2 Dimension(mm): Subwoofer 220*264*348;Satellites 100*206*106 Frequency Rang:Subwoofer 60~180Hz; Satellites 150~18KHz Impedance:4ohm S/N:e70dB * MP3 Decoder 2.4G built-in(USB/SD)