|| The Smith Threshold Polarized Sunglasses feature four interchangeable lenses so you can match tints to current light conditions and activities. Polarized lenses offer anti-glare protection under extremely bright conditions, perfect for snow and water activities. Each frame includes one set of polarized lenses (tint depends on frame color) and three additional sets of lenses for a total of four sets of lenses. Non-polarized, additional lenses (rose copper, yellow and clear) are ideal for low- and medium- light to night time conditions. Scratch- and impact-resistant Carbonic(TM) lenses easily slide in and out of frames for fast switches. Durable Grilamid(TM) nylon frames wrap slightly around face for peripheral protection from wind, snow and glare. Hydrophilic nosepiece and temple ends become tackier when wet for reliable grip during exercise. Metal hinges ensure smooth action and long wear. Threshold sunglasses are sized to fit a medium- to large-size faces. Case included. All frames also include two additional lenses, rose copper tint for a wide variety of conditions and yellow for extreme flat and low light conditions.