In the words of Mythos Pedals:

The Argonaut is a no frills pedal offers a clean-ish octave up sound. Using it alone offers you a gnarly, ring mod-esque sound that is pretty funky. The fun begins when you combine it with your favorite overdrive or fuzz pedals. Once combined all the iconic octave tones we know and love begin to jump out of your signal. Its very touch responsive, weird, and fun all rolled into a small little package. The Argonaut uses a pair of Hand matched NOS Germanium Diodes, this gives the most prevalent octave up effect that is present all over your guitar neck. Unlike traditional octave pedals the octave effect can be heard up and down the guitar neck, so get ready to get weird once you add this bad boy to your setup.