Surpass ANSI Z87.1 Industrial Standards for high-mass and high-velocity impact protection with the Oakley SI M Frame. It incorporates High Definition Optics (HDO) technology with a lens geometry that comes in five interchangeable lens shapes. The lenses are pure Plutonite, which gives the highest level of optical clarity available. All angles of view are seen in razor-sharp clarity to maximize peripheral vision along with protecting against wind, side impact and sun damage. Lens Descriptions Clear Lens - All-purpose. The maximum amount of light is let through so you get the most accurate representation of the environment | Gray Lens - It has enhanced contract for sunny conditions, which makes it an excellent all-purpose lense.