Zeal Tenacious polarized photochromic sunglasses provide eye protection against the sun and help you see better in all of your outdoor activities. Photochromic lenses automatically respond to changing light conditions, darken in bright light and lighten in dim light in mere seconds. Polarized lenses reduce 99% of visible glare from water, snow, sand and pavement for increased visual acuity and decreased eye strain. Lightweight nylon frames offer a consistent fit and flexibility in all temperatures and are extremely impact resistant. Easy-flexing spring hinges accommodate a multitude of head sizes. Silicone nose pads and temple ends grip during exercise and hot weather for a secure fit; reverse the nose pads to tailor the fit to your face and eliminate eyelash contact. Includes a semirigid hardshell carrying case and a soft microfiber case which doubles as a cleaning cloth. Best fits medium-large profiles.