Two Phase 90 circuits in a single Phase 90-sized housing Separate rate controls Modern & vintage series to parallel and sync switching controls The MXR Phase 90 sits with the Cry Baby® Wah Wah and the Fuzz Face® Distortion as one of the truly iconic effect pedals in music history setting the standard by which all others in its category are judged. For years experimental players have used two Phase 90 pedals side by side to create amazing textures from the way the two circuits interact with one another. Now you can access the same sounds in a single pedal. The MXR Custom Shop Phase 99 opens up the sonic palette of the iconic Phase 90 by combining two phase circuits into a single Phase 90-sized housing. Separate rate controls for each circuit allow you to create intense complex phasing and a Vintage switch toggles between modern and vintage style phasing. Further the Phase 99 features a P/S switch to toggle signal flow between the circuits from series to parallel and a Sync switch to synchronize the rate of each phase circuit.