Mooer's Thunderball pedal features two working modes: Fuzz and Dist. Fuzz mode provides a classic fuzz tone, perfect for bass. Dist mode is an old style overload sound blended with the original signal. The Thunderball is designed to accommodate bass frequencies and add distortion, fuzz filtering without degrading the fundamental tone and signal. A full metal shell ensures good service for many years and a true bypass protects the integrity of the original signal when the effect is not being engaged.