Boll X9 OTG Modulator Ski Goggles are designed to fit over most prescription eyeglasses always a good idea to be able to see where you're going, while schussing down the slopes. Double lens creates a thermal barrier, providing exceptional optics and a superior seal. The Bolle X9 SkiSnowboard OTG goggles are designed to fit over most prescription glasses. Flow Tech Venting designed to reduce fogging and optimize the flow of air over the inside of the lens. The state of the art venting not only controls airflow, but prevents clogging from ice and snow. Double PC Vented Lens The Bolle unique double lens design creates a thermal barrier, while providing exceptional optics and a superior seal. P80 PlusCarbo Glass is the proprietary Bolle technology which is applied to the polycarbonate lenses it provides maximum protection against fogging and scratching. Triple Layer Face Foam is micro soft on your face, and backed with two layers of dual density foam for a firm yet soft fit. Perfect Helmet Fit is engineered with the latest helmet designs in mind so the fit is smooth and comfortable.Lens info: Modulator Vermillion: A state of the art, high contrast, light sensitive lens that changes lens tint density with the changing light conditions. The brighter the sun light exposed to the lens, the darker the lens will become. This lens is good for night conditions, snowy days to partly cloudy, even bright sunny days. The % of visible light transmitted changes from 66% to 26%.