I have never been more frustrated with a pair of sunglasses than I am these.  They will not stay where they are supposed to.  Bend over and they slide off.  Go outside in the heat and get slightly sweaty, they slip down my nose.  Every other pair of similar designed sunglasses I've owned I've been able to put on top of my head when I enter a building and they stay there, but not these - they fall off.  The blue is beautiful, and the lenses provide a crisp and clean view, but the fit is absolutely terrible.