Prohibits initial fog formation and provides long-term anti-fog performanceand rainproof . It is an innovation that solve your trouble of unclear visibility through rear view mirror during foggy/winter days.and rainy day also effectiveNote : Apply it from the inside for better use and durability than Outside useProhibits initial fog formation and provides long-term anti-fog performanceand rainproof . It is an innovation that solve your trouble of unclear visibility through rear view mirror during foggy/winter days.and rainy day also effectiveNote : Apply it from the inside for better use and durability than Outside use