The Giro Contour goggles uses the Quick Change Lens System to swap lenses. The lenses are held in place by magnets running along a rail inside the frame of the goggles. So to remove a pair of lenses, you need to pick a side to tear away the lens, this should be relatively easy. To put in the new pair of lenses, just place the new lenses in the frame and the magnets will hold them in place. , Removing the lenses on Giro Contour goggles is easy and can be done in 2 steps. Simply grip the frame of the goggles with one hand, and grip the edge of the lens with the other. Gently pull your hands in opposite directions, and the magnets should release. To install a new lens, align the center of the new lens with the center of the nose and brow and apply pressure to snap lens to magnets. Then along both sides, gently apply pressure to secure the 2 pins on each side.