Vapor Shield “military grade” anti-fog is the world’s first true anti-fog technology, and is a permanent anti-fog solution that is absolutely impervious to fog, vapor and condensation in the most extreme conditions and temperatures. The Edge Vapor Shield Lenses have passed the following tests with NO fogging: -42°C for 15 minutes, Transition from -42°C to 24°C, Transition from 24°C to -42°C, 52°C with 80% humidity