The XP stands for extra protection, and the larger lenses on the Native Eyewear Dash XPs provide greater coverage, while interchangeable lenses provide maximum clarity in most any light condition making these sunglasses a great choice for a variety of activities.. . . . . . . 100% UVA and UVB protection with polarized silver Reflex lens to reduce glare. Strong, lightweight frame Ryhno Tuff Air frames. Cushinol padding at nose for superior comfort and stability. Frame vents to reduce fogging. All Native lenses pass the ANSI Z80.3 test for impact. Includes nonpolarized SportFlex lens for low light conditions. XP extra protection lenses are 20% larger for more addition coverage. Semi rigid case included. Best fit for medium sized faces.