Compressor effect pedal to improve sound quality. - Model Name: COMPRESSOR - Brand Name: Musiclily - Input Voltage: DC 9V - Control Knobs: LEVEL, COMP - Type: Effect Pedal Purchased new and used for about a year in studio practice. It has been used sparingly and has been cleaned thoroughly. The effect has also been confirmed to be working. Please note that it does not use batteries and requires an adapter power supply only.