Keeley produced the KMONT-U Monterey Rotary Fuzz Vibe as a multi-effects pedal combining a fuzz channel with a modulation channel offering rotary, vibe, and wah sounds. It was positioned as a unit that drew on neo-vintage effect types while offering modern interpretations of those sounds for guitarists.

The fuzz channel centred on a two-transistor fuzz circuit built around vintage Fairchild Semiconductor transistors, described as moderate-gain devices. The modulation channel provided three selectable sounds: a vibe mode referred to as "Kool Vibe," which combined phasing and tremolo and simulated a photo-cell based effect; a rotary mode referred to as "Les Rotary," which modelled both the lower drum and upper horn of a rotary cabinet; and a harmonic and auto-wah mode. An Octave control was shared across the vibe and wah sounds, with a centre position delivering no octave effect, clockwise rotation adding octave up, and counter-clockwise rotation adding octave down. The unit featured two footswitches — the right activating the fuzz channel — and an expression control input. The pedal also provided five configurable sound combinations across its two channels.

Owners requiring adjustment or repair of the circuitry, footswitches, or expression input should consult a qualified guitar technician or electronics repair specialist familiar with effects pedals.