The Smith Parallel D-Max Sunglasses were designed with cycling, running, and other active outdoor pursuits in mind. The medium-sized frame boasts extra-large lenses and a nine base curve for a good, snug fit with adequate coverage. When the light changes, swap out the lenses with the included lenses to provide the right definition. Evolve frame material utilizes FSC-certified reground material that is 100% recyclable The scratch-resistant Carbonic TLT (Tapered Lens Technology) lenses provide supreme clarity and distortion-correcting optics (the lens is thicker in the middle and tapered towards the outer edges) so you have a true optical center Hydroleophobic lens coating is applied to the top of the lens to repel moisture and grease and make cleaning easy9 Base lens curvature provides a deep wrapping effect around your face Includes two extra sets of easily interchangeable lenses (clear and Ignitor) in addition to the lenses already in the frame for a total of three lenses Ignitor lenses provide maximum definition on medium cloud cover to overcast days Clear lenses are ideal for extremely low-light conditions or even night time