I bought these for running having had quite a few pairs of other glasses that just didn't do the job for one reason or another. These glasses are light as a feather and they stay exactly where you put them! No bouncing or slipping down your nose at all! The polarised lenses are really good especially moving from bright sun into shade and out again. I ran a near pb parkrun this morning on a hilly and twisty course and the glasses passed the test. Love them!