Tifosi isn't in the business of making cheap eyewear. Rather, when you're wearing them it's a challenge to distinguish their optical quality from that of glasses twice or three times the price. Their Slip Fototec model gives you a wide field of vision that's totally distortion-free, and you'll benefit from lenses that transition from light to dark automatically. You'll think you're wearing a pair of $200 shades. The High Speed Red Fototec Lenses are Tifosi's darkest Fototec lenses. They'll darken from 35 to 12% total light transmission in less than ten seconds. With these lenses, you'll have clear vision in all light conditions during your training rides or races. You won't be at the car fidgeting with lens when you should be at the start line getting ready to roll out. The Slip glasses are shaped so they fit the full range of face sizes. The frames are made with Grilamid TR-90 - a nylon with exceptional bendability, strength, and toughness against impact and UV damage. Not only are they virtually indestructible, but they are all-but-weightless, allowing the Slip to weigh in at an amazing 25g. Once you have them on they stay in place, too, thanks to their hydrophilic rubber adjustable temples and nose piece. Other Slip highlights include ventilated lenses for increased air flow and greater resistance to fogging. Tifosi also includes a carrying case and a Microfiber lens wipe. Fototec lens with variable tint technology adjust rapidly as light conditions change (lenses get light in the shade and dark in bright sunlight)Grilamid TR-90 nylon is lightweight, comfortable, and resistant to chemical and UV damage Hydrophilic rubber ear and nose pieces provide no-slip fit and increase grip when they come in contact with sweat Adjustable temple pieces allow you to customize your fit while increasing comfort when worn under a helmet or over a hat High Speed Red Fototec lenses sharpen contrast and highlight details in the road or on the trail Light Night Fototec lenses chang.