These clip-on sunglasses are just great!  They are the size advertised, are easy to apply and have great optics and sun-glare reduction.  Before I had these, I kept dropping sunglasses I had removed when things got cloudy, or if I wanted a quick look at my phone screen.  Now I can just flip them up and see what I want, then flip them down when needed...and my prescription glasses remain so I can see either way.  If I won't need them for a while, I can either clip them on my ball cap bill and they're out of the way but safe, or can put them in the case until needed.  Great for being around water or on a bike.