Used Keeley Fuzz Bender

Hybrid Circuitry: Blends the reliability and aggressive high-gain nature of silicon with the organic, soft-clipping warmth of vintage germanium.

• Active 2-Band EQ: Unlike traditional squarewave fuzzes with a single passive tone knob, it uses dual gyrators to provide up to 20 dB of active boost or cut at 100 Hz (Bass) and 10 kHz (Treble). This allows you to sculpt your low end or pierce through a dense mix without losing definition.
• Gated & Velcro Bias Control: The dedicated Bias knob alters the voltage to the transistors. It lets you dial in anything from a fat, singing, fluid sustain to starved, sputtering, sub-biased glitchy "velcro" textures that decay abruptly.
• Power & Footprint: Runs on standard 9V DC negative-center power with a low current draw of 15 mA (battery operation is not supported). It features a rugged, compact metal chassis measuring 95 x 110 x 50 mm.

The Fuzz Bender stands out because it behaves like an instrument itself; it responds dramatically to adjustments on your guitar's volume knob and allows you to emulate multiple generations of fuzz style in one enclosure.