This is a Stellartone Tone Styler Micro pedal. It's a passive, high-impedance, 100% analog tone module for the guitar or bass. It produces 15 discrete EQ contours plus true bypass. It uses no batteries, and adds zero noise or distortion to your instruments output signal. Check it out at Stellartone.com for more details. The advantage of the Micro Pedal is that you can use it with a variety of different guitars or basses. I like it so much, I'm having it built into a custom bass, therefore I no longer need the pedal itself, just the drop-in model This one is optimized for the bass range although it certainly works great on my guitars too. Finally, note that it only works with passive instruments, not active ones. Instruction sheet included. The "list price" is $174, and the "street price" is $145. I'm letting this go for $95. It's barely used.