We are manufacturer, professional amplifier. 1,250W 2,USB playing, radio station. SD card. 3, 70/100V. 4-16ohm. 4, +_3dB ModelRated powerOutput modeInput sensitivityS/n ratioFred ResponsePower workDimensionsMC-2250250W70-100V4-16Ω500mv>85dB80Hz15KHz±3dBAC220V±10%/50Hz 90 χ485 ×4301.Directly record at MP3 format.2.Connect PC with USB interface, doenload and update music freely.3.Play music on time ...