The TC Electronic Polytune Noir is compatible with a few alternate tunings. It allows you to switch to Drop D, and 15 other tunings that consist in lowering every string by the same number of semitones, or placing a capo between the 1st and 7th frets. Sadly, it doesn't offer support for other popular tunings such as DADGAD, Open G, Open E, etc. It still features chromatic tuning, so if you know the pitch of every string within an alternate tuning, you can still achieve it easily.