The Fulltone Fat Boost is a highly regarded Class A JFET booster pedal designed to add warmth, body, and up to 30-35dB of clean gain to a signal. Known for its ability to push amps into natural, rich overdrive without altering the fundamental tone, it works well with various guitars, particularly improving single-coil "thinness," and features interactive controls for shaping tone and driving the front end of amplifiers.

• Class A FET Design: Utilizes JFET technology for a tube-like, dynamic, and compressed feel.
• Versatile Tonal Control: Most versions offer controls for Volume, Drive (gain), and passive Bass/Treble adjustments.
• Version:
• FB-1 (V1): Original version, renowned for its "thick and punchy" sound and 30dB boost.
• Functionality: Acts as a clean booster, a light overdrive, and a tone-shaping tool to brighten or darken an amp's input.

The pedal is known for being ruggedly built with high-quality components, often described as a "always-on" pedal for boosting and enriching a guitar's overall signal.