Base Curve: 8 Tr90: TR90 is thermoplastic material produced in Switzerland it is incredibly durable, flexible, and lightweight Polycarbonate: Polycarbonate is lightweight, comfortable, impact resistant, and provides UV protection. Rimless nylon shield lens offers widest field of vision and unobstructed view. Impact resistant and no cracks, no chipping during lens glazing.Ventilation and/or top-bar engagement slots. Double-molded clip-on bridge with adjustable nose pads. Fully adjustable endtip with metal core covered with anti-slip, non-allergenic rubber for maximum snug fit. Shield lens(w/ 7-base front curve) pre-cut with eye opening when ex-factor with standard nylon groove (0.7x0.7mm groove size, 7 to 8-base groove curve). Frame, lens color designs inspired by pro cycling team jerseys.