FC stands for Full Coverage and that is what this model offers: complete full coverage lens protection in a half frame. . The Tifosi Jet FC features a sporty aggressive design perfect for any athlete. Made of Grilamid TR-90 an incredibly light and durable nylon material that resists chemicals and UV damage. The Smoke Red lens is a perfect lens for cycling running and active sports when the sun is high and the sky is a deep blue. The neutral tint of smoke lenses prevent color distortion.