» The new Xotic SP Compressor offers the same OTA (operational transconductance amplifier) technology used in what many guitar players consider the best compressor ever, the Ross Compressor. » Our new SP Compressor has superb tone quality featuring a wide variety of compressor tones from vintage,to subtle, to modern and more. It's super flexible and features a dry blend knob, up to +15dB of boost and an internal dip switch for attack control. » This compact design is a powerful tool for the working musicians. » True bypass for eliminating any signal interference when switched off. Can be used with AC adaptor (optional) or 9V Battery. Dimensions (W/D/H): 3.5" x 1.5" x 1.5" (89mm X 38mm X 38mm) Weight: 0.57 lbs. (260g) True Bypass Switching Power Consumption: 9VDC/5mA Battery Type: 9VDC (006P) x 1 AC Adapter (Optional): 9VDC, Negative Tips (Regulated) Input Impedance: 1M ohm Output Impedance: 10k ohm