LensCovers are perfect for anyone who wants the benefits of sun protection while wearing their glasses. They're lightweight and easy to slip on over your glasses. You'll want to keep a pair in the car, office, house or wherever you need them! LensCovers are designed to wrap around your face blocking the sun from the side as well; a practical alternative to expensive sunglasses! LensCovers are polarized, providing increased clarity, reduced eye fatigue, and glare protection. How to measure your frames for LensCover sunglasses: 1- Measure the widest part of your frames left to right, this is the "width". Next measure the height of the lens with frame included. 2- Choose the LensCover frame (below) that is slightly larger in width and height than your frame measurements. LensCovers Extra Small is 4-15/16 inches x 1-1/2 inches high LensCovers Small is 5-5/16 inches wide x 1-5/8 inches high LensCovers Medium is 5-1/2 inches wide x 1-3/4 inches high LensCovers Large Slim is 5-11/16 inches wide x 1-7/8 inches high LensCovers Large is 5-3/4 inches wide x 2-1/8 inches high For example, if your frames measure 5-1/4 inches (width) x 1-1/4 inches (height), the correct LensCovers Frame would be size Small. Hard Case for LensCovers are available under a separate listing.