Prescription sunglasses are essential if you are a glasses wearer and like going outside on sunny days. However every time you need a new prescription, you have to replace the lenses in both your glasses and sunglasses. Plus you have to carry around another pair of frames in a case all the time. I mean, what's that all about? Amirite?
By having a custom clip on made, you only need change one pair of lenses, you'll have just a small box to slip in your pocket for the clips and you'll look all Johnny Cool too.