The Smith Knowledge Turbo Fan OTG Goggles has a large interior volume that accommodates a wide range of eyeglass sizes and now with the new 5X Anti-Fog Inner Lens, the Knowledge is an excellent choice for all eyeglass wearers. Featuring a two-speed, micro electronic fan for maximum ventilation. Distortion free Carbonic X Lens with TLT Optics and patented Vaporator Lens Technology with Porex Filter. No more putting your goggles on at the lodge and leaving them on all day. Keeps both your glasses and vision clear even in changing conditions.