Essentially, the Cntl Knob allows you to set two preset values on any pedal with an expression output jack.
There are two knobs to control the presets - fully counter-clockwise is the heel position, while fully clockwise represents the toe-down.
In addition, there’s a TRS+/- button to match the Cntl Knob’s expression polarity to your pedals, while LEDs indicate which knob is active. It runs from a standard 9V power supply.
The Cntl Knob marks the first mini pedal we’ve seen from Electro-Harmonix - which hopefully points to more in the not-too-distant future.
With that small form factor, we expect to see a bunch of these cropping up on pedalboards - especially given the $39 asking price, which even includes a six-foot TRS cable.
For more info, head over to EHX.