The SI Flak 2.0 XL are high-quality safety glasses from Oakley. The side curvature of the lenses with 8.75 BC extends peripheral vision and improves side protection against sun, wind and impact. High Definition Optics® (HDO®) is a collection of patented technologies, which allows the production of Oakley eyewear that meet or exceed all testing standards of the American National Standards Institute (ANSI) with respect to optical clarity, excellent visibility and impact resistance. This high-quality glass coating of highly heated metal oxides ensures balance in light transmission and reduces glare. It is available in a variety of colors and optimizes visibility under virtually all lighting conditions.