Oakley flak 2.0 xl photocromatic sunglassesflak 2.0 xl offers an xl size frame with enhanced lens coverage, and every millimetre of the lens is optimised with high definition optics in a ruggedly durable yet lightweight design that takes performance to the next level and brings style along for the ride.designed to push your limits with patented xyz optics for razor sharp clarity and secure grip of unobtanium features the xl edition offers enhanced lens coverage and specialised 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 protectionbuy oakley accessories from chain reaction cycles, the world's largest online bike store.