Enhanced performance, lightness and durability make Oakley Flak 2.0 Sunglasses a go-to piece for hikers, bikers, skiers and mountaineers. OS means one size of standard fit.Built to perform whatever your adventure, Oakley Flak 2.0 Sunglasses feature Prizm lens technology which enhances colour and contrast to bring the detail into focus. The lightweight frame has a performance fit which features secure Unobtanium earsocks and nosepads for an outstanding fit.Lightweight O Matter frame material with ellipse metal icon accentsUnobtainium earsocks and nosepads for increased comfort and performance8.75 base lens geometry with HDOFeatures Prizm lenses to enhance colour and contrast so you can see more detailImpact protection - designed and tested under extreme high mass and high velocity circumstancesProtective soft vault includedColour: Matte Black