The Oakley SI Half Jacket 2.0 XL is sculpted to fit comfortably around the head while maximizing visual performance. Using innovative Prizm technology, the lenses enhance vision by strategically blocking wavelengths across the color spectrum, maximizing color contrast and allowing targets to stand out against foliage or the sky. The O-Matter stress-resistant frame is designed only to make contact with the bridge of the nose and the sides of the head for a comfortable fit. An Unobtainium finish actually increases the grip when wet, helping the glasses stay in place when you're sweating or working in wet weather conditions. The lenses filter out 100% of all UVA and UVB rays in addition to harmful violet-blue light up to 400nm in wavelength.