The ZVEX Mastotron is a versatile, heavy silicon fuzz pedal designed for both guitar and bass. It features unique controls such as Relax/Push, which adjusts input impedance to accommodate various pickups and sound sources, and Pulse Width, allowing modification of waveform shape for diverse tonal textures. Additionally, a three-position Subs switch tailors the pedal's low-frequency response, making it adaptable to different instruments and amplification setups.