I'm a carpenter by trade and can tell you that it's not a square. It does however look like some kind of tiedown/binder, the two knobs on right with the cammed handle on th left. what kind I don't know.
OK, I had a memory lapse, I've used something like that before to laminate something together after putting in a biscuit joint. I forget the name but it's a "quick clamp" of sorts hope this helps.