Switch Your Old Lenses For Some Shiny New Ones, Replacement Lenses Are Available For Select Styles. Keep In Mind That If You Replace Any Other Parts Your Warranty Will Become Void.Photochromic:- Built With Oakley Hdo® Technology, Photochromic Lenses Automatically Adjust To Changing Uv Light Exposure While You'Re On The Go.Specifications:- Light Transmission: 23%- Light Transmission (Activated): 23%- Light Conditions: Changing Conditions- Contrast: Neutral- Base Lens Color: Clear