ROCKBROS Bike Polarized Cycling Glasses CS010 TR90 SWITZERLAND: A Swiss technology, this thermoplastic is the material used in all of our sunglasses. Its extreme flexibility, durability and light weight make it the perfect material for performance eyewear. Ultra Lightweight: As with any piece of high-performance equipment, weight is an important factor. TR90 is incredibly lightweight, which contributes to the comfort of our eyewear and the tendency to forget you're wearing it. Polycarbonate Lens Material: Polycarbonate is the extraordinarily durable thermoplastic that's used in bullet proof glass, riot shields and astronaut helmets. It's the ideal material for performance eyewear because of its high impact resistance, inherent UV protection and light weight. All of our lenses are made of polycarbonate. UV Protection: All of our lenses block 100% of UVA, UVB and UVC rays, and harmful blue light to 400nm. These harmful rays are a leading cause of cataracts, skin cancer and wrinkles around the eyes-all great reasons to block them out.