TheOakley Flak 2.0 XL Photochromic Glasses. 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 HighDefinitionOptics® 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® Oakley Flak 2.0 XL Photochromic Glasses Features 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™ stress-resistant frame material is both lightweight and durable for all-day comfort and protection