frameless design with two sigmaâ„¢ lenses. the sentry prime offers a frameless design and exceptional optical quality. whether filming new tricks or carving epic lines through the powder, the sigmaâ„¢ lenses ensure clear vision in various weather conditions. thanks to salomon's unique frame construction and custom id fit technology, the goggles instantly adapt to the shape of your face.sigmaâ„¢ black gold lensthe sigmaâ„¢ lens enhances colour contrast, allowing you to see terrain details in all light conditions quickly.light transmission 13 %