We need more information with regards to this as there was no description provided by YZH on these lenses which can be used as replacement for the Emerson FAST Helmets with Goggles already included. We can't say if these are three types of lenses or this is a photochromic ones, with the photos showing the various shades of the photochromic lens under different lighting conditions. If photochromic, no need for changing lenses.