Xotic BB Preamp-Comp Custom Shop, Boost/Compressor/Distortion, analog, 2-Band active EQ, 3 Compression levels, GAIN: controls the level of Boost, VOLUME: adjusts the volume, TREBLE: adjusts treble, BASS: adjusts bass, COMP switch: 3 settings - Normal, Comp, Neutral, ON/OFF status LED, 6.3 mm jack in- and output, True Bypass Switching, Metal housing, Power: 9V or optional 9VDC power supply with 2.1 x 5.5mm barrel plug Polarity: center (-), ring (+), Dimensions (D x W x H): 11 x 6 x 5 cm, Made in USA,