This product has been tested and confirmed to be working. It requires a 9-volt power adapter. The power adapter is not included. Please note that this is a used item and may show some signs of wear and tear. Returns are not accepted. Link to a video demonstrating the functionality: https://youtu.be/EU6I4tpKcQY?si=DTz9XVHEkzCYh-I9 The Electro-Harmonix Little Big Muff is a guitar effects pedal with adjustable volume, tone, and sustain. - Model Name: Little Big Muff - Brand: electro-harmonix - Functions: Volume, Tone, Sustain adjustment - Input Jacks: 1/4 inch jack - Country of Manufacture: USA Thank you for viewing.