The Trieye eyewear glasses with integrated adjustable mirror will give you a completely different experience when rowing - A Game Changer. You can see in the mirror if you are rowing in the right direction without turning your head around, and maybe be sure that the boat coming from behind sees you?! The frame is made from TR90, a thermoplastic material that is incredibly durable, flexible, and lightweight. Frames made with TR90 are comfortable to wear because they bend under pressure and contour your face comfortably. Rubber tip for max comfort. Durable, lightweight and scratch-resistant Polycarbonate lenses with TriEye Mirror House so you can watch you're back. Fully UV protected (UV400), Category 0-2. Photochromic: The lenses will change colour due to exposure to ultraviolet light, from category 0 in the dark/inside to category 2 in sunny weather. The best solution for an all-around lens for all kinds of weather