Varioflex is a lens technology in which the lenses automatically adjust to the weather. The self-tinting (photochromatic) lenses on the Altona V spare visor react to UV light. When exposed to radiation, chemical elements "open up" and create a comprehensive darkening effect. When the light intensity decreases, the chemical elements close and the lens becomes brighter again. This process takes seconds. The Altona V replacement visor is also mirrored, protecting against glare. It provides 100% protection against UV-A, UV-B and UV-C rays.