Welcome, You are looking at a great piece. This is the Enigma Q-Balls Bass Envelope Filter! This awesome envelope filter is designed specifically for bass frequencies. This pedal ranges from 40Hz to 3kHz so you can get a big, even sweep. Between the Blend, Q, Filter Type, Attack, and Decay controls you have more than enough adjustmenst to dial in the exact envelope filter sound you want. Plus, you can add some edge to your tone by pushing the distortion button for extra grit. This is a great pedal for grooves and funk bass as well as many other styles of playing. The Enigma comes with the power adapter so you are ready to play as soon as it arrives at your door! Check out the video link to see a great example of this pedal's capabilities. We are an authorized Electro-Harmonix dealer. Don't pass this by!