This 3699 is based on a Foxx Tone Machine which had a much more complex circuit than the standard fuzzes of the era and included an octave up on a toggle switch.
Interestingly Danelectro is now owned by Steve Ridinger, the man who created the original Tone Machine in 1971.
The Octave is now footswitchable and the pedal features a mid push toggle switch for cutting through a mix nicely.