I purchased the Oakley Flak 2.0 XL sunglasses with the Prizm Trail lenses. I use them mainly for mountain biking and hiking in the woods. I needed a lens that lets in a lot of light with good eye protection. They are lightweight, stay in place and everything looks awesome through the lenses. The lens is ideal for forest use but not enough for direct sunlight, so I will likely purchase a darker lens for road biking.