The Smith Knowledge Turbo OTG With RC36 Lenses has a large interior volume to accommodate a wide range of eyeglass sizes while also fueling the fog-fighting performance of our patented Turbo Fan technology. Combined with our proprietary 5X anti-fog inner lens, the Knowledge provides incredible anti-fog performance for eyeglass wearers. The RC36 Lens has 36% Visible Light Transmission. Universal lens tint combines rose and copper base tints. Improves depth perception, increases contrast and cuts glare in all conditions.