... price,support sell in group with musical instruments. Professional USB multi Speaker muscial instruments amplifierModel : M2600-210 Power : ... ,bass independent proportional-plus-floating control. 3 group microphone inputs, microphone treble ,bass,reverberation depth, reverberation speed regulation. ... . 2 groups pretage outputs. bulit-in compressor. USB connector, can be inserted flash card, mp3,mp4,SD ...