Oakley engineering takes performance to the next level and brings style along for the ride. Flak 2.0 offers a standard size frame with enhanced lens coverage, and every millimeter of the lens is optimized with High Definition Optics® in a ruggedly durable yet lightweight design. Designed to push your limits with patented XYZ Optics® for razor sharp clarity and secure grip of Unobtanium® FEATURES - PRIZM(TM) is a revolutionary lens technology that fine-tunes vision for specific sports and environments - The XL edition offers enhanced lens coverage and specialized lens curvature for protection against sun, wind and impact - Unobtanium® earsocks and nosepads keep glasses in place, increasing grip despite perspiration - Patented High Definition Optics® (HDO®) provides superior optical clarity and razor-sharp vision at every angle - O-Matter(TM) stress-resistant frame material is both lightweight and durable for all-day comfort and protection