Oakley engineering takes performance to the next level and brings style along for the ride flak 20 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 unobtaniumfeatures prizm is a revolutionary lens technology that fine tunes vision for specific sports and environments the