The Smith Knowledge OTG With Ignitor Lenses has a large interior volume to accommodate a wide range of eyeglass sizes. Combined with our proprietary 5X anti-fog inner lens, the Knowledge provides incredible anti-fog performance for eyeglass wearers. The Ignitor Lens has 35% Visible Light Transmission. Proprietary universal lens tint designed to reduce eye fatigue while enhancing contrast and depth perception in all conditions. A versatile lens tint designed to be used all season long.