Smith Optics Threshold Interchangeable Polarized Sunglasses features an extremely lightweight, sporty design. Smith Optics unique Interlock design allows for easy removal & replacement of your lenses to cater to any light conditions. The Threshold contains polarized lenses to eliminate any unwanted glare while protecting against harmful UV rays. Threshold Sunglasses can be customized with a variety of lens tints to compliment the brightness of the day.