The Electro Harmonix Nano POG is the smallest member of the POG family. EHX's line of Polyphonic Octave Generators offer some of the cleanest tracking of any pitch shifting effects, and they sound simply incredible. The Nano POG is a bare-bones option, but still sounds just as good as its siblings.
The POG series overcome all of the issues common to pitch shifters: they track chords with no problem, and handle bends, sweeps, and anything you can throw at them without breaking a sweat. Offering individual level controls for Sub Octave, Octave Up, and Dry signal, the Nano POG is EHX-quality pitch shifting at an awesome price and an awesome spatial impact.