This is a Real Tube brand rack mountable guitar tube preamp & overdrive for boosting guitar amp power, add tube overdrive or can be used with a power amp only if desired. Simple to use with knobs, no required processing setup, just a great guitar preamp with a clean & dirty sound as needed. Rear panel allows footswitch and other input/outputs. For more information call 337-424-5089. If no answer, please leave a message and I will return your call.