Customize the look of your flak 20 xl eyewear and get the best optical performance for where you use it most all replacement lenses feature the unbeatable clarity impact resistance and 100 uv filtering of oakleys high definition optics hdoimportant notereplacement lenses may not be returned if they have been mounted or scratched asian fit lenses cannot be installed in standard size eyewear framesintegrated technologieshigh definition opticshigh definition optics hdo is a collection