Octave on Bass is such a tradition tone that it's hard to imagine a bass players pedalboard without one. This pedal hit the market in 2009 and has been seen on boards throughout the bass world since, in part that is due to how simple to use yet variable it it is. Basically the pedal is split into two halves, clean and octave. On the Clean side the tone adjusts the bass/ treble mix allowing you to match or counterpoise the octave effect against the Octave Filter control which adjusts the octave from sharp and aggressive through to bold clear subs.
The results are anything from subtle through to synth tones which is why this pedal is so popular.