The Smith I/O Goggles With Blackout/Red Sensor Lenses intuitive quick release lens change system is tried and true, so you can switch lenses and stay out in the most demanding conditions. The spherical lens has 5X anti-fog, Smith’s highest level of anti-fog technology, and TLT optics for crystal clear vision. The I/O was the original goggle to solve the problem of what to do when changing light and weather demanded different lenses. The Blackout Lens has 10% Visible Light Transmission. Dark gray base lens tint cuts glare and reduces eye fatigue in bright, sunny conditions. The Red Sensor Lens has 55% Visible Light Transmission. Light rose base lens tint with a multi-layer red sensor mirror maximizes color definition and increases depth perception in varying levels of flat light conditions.