Features:U disk SD/MMC card can be played for music and FM stereo radio and this item Supports MP3 music format (USB+SD+MMC+FM)Four channel， integrated circuits， minimal distortion and strong power1 main channels and 1 surround channel outputFiltering and anti-capacity power circuitDSP sound field pattern of the fourIdeal for your Car， Motorcycle， Boat， etcFrequency Response: 20Hz- 20KHzOutput Power: RMS 50W 1KHzHarmonic Distortion:?? 0.05% 5W 1KHzSNR: ??85dBHigh Control: 12dB??10KHzBass Control: 12dB??100HzSignal Level: 220MV 47KReader， U-disk Format: MP3， FMFM Frequency Range: 87.5MHz-108MHzDimension: Approx. 10.2x8x4.1cm/ 4.02x3.15x1.61''Package Included:1 x 2 Channel Audio AMP Amplifier