On a recent vacation I discovered these ROAV sunglasses. They are sweet. Made of stainless steel, polarized and they fold up into something the size of 4 credit cards stacked together.
Pictured hear are the Echo in black which I now own and have been using for the past few weeks
There are a number of styles and sizes. I fit the large to medium size head and recommend you look at some of the photos to be sure.
The reason I love these sunglasses is that I can wear them out to dinner and then fold them up and place them in my pocket and not have to fuss with a sunglasses case or even possibly loose them.
I keep these in my bag and carry them with me at all times now so that I always have a pair of sunglasses.