Otherwise known as cutoff frequency on many other pedals. No wonder folks get confused about controls when manufacturers don’t use the accepted terminology.
Definitely Cherry Sunburst and not Honeyburst this one.
Not often you see a single-piece body on these. Lovely bass. I’d have been on this had it been a different fingerboard and finish.
The “peak” on the Proton is the resonance control. I much prefer the envelope detector on the Chromatron (same as Proton 4) compared to the Wonderlove I had.