This looks exactly like one of those cheap gifts I would have found for my Dad when I was a kid.  In fact this was actually done by a Dutch designer, Paul Baars, so clearly I had excellent taste as a child.  This tiny little level can be pinned to a tie a or even used as a brooch.  With this you can tell just how straight someone is sitting.  It can be purchased for $11.55 from the Grand Illusions Toy Shop.

Source: UberReview