The Ultimate Octave guitar effects pedal from Fulltone is a fat distortion/fuzz with a very active tone control and a separate switch that kicks in the most searing octave-up available. In addition to volume, tone, and fuzz controls, the Ultimate Octave effect also has a Fat/Bright switch that completely changes both the distortion and octave sounds from strong, thick mids (Fat) to completely scooped out with no mids and lots of bass and high end (Bright).

Ultimate Octave devotees include:
Joe Satriani
Joe Perry
Neal Schon
Wally Farkas
Scott Henderson
Primus
Billy Gibbons
Ian Moore