Got this a few days ago but somehow misplaced it. It's an intonation adjust, let's not confuse it with a tuner.
What it does- locks itself to the Ibanez bridge saddle for intonation adjustments. This is necessary when your open strings & fretted notes are in tune but not past the 12th fret. You have to move the saddles away or towards the body end depending on whether the notes are flatter or sharper than required. Before this acquisition, I've been crudely moving the saddles by hand & it's a trial & error method as opposed to using this adjuster. It allows me to hold the saddles in place while a re-tightening takes place.