The Smith I/O Snow Goggles are the original interchangeable goggle that invented the category. The I/O is now the standard by which all other goggles are measured. The Gold SOL-X Mirror (7% VLT) is a S4 Category lens with dark sienna brown, Sol-X base lens tint with a multi-layer gold mirror cuts glare and reduces eye fatigue in sunny conditions. This model also includes a Red Sensor Mirror (60% VLT) is a S1 Category lens with a light rose base lens tint with a multi-layer red mirror that maximizes color definition and increases depth perception in varying levels of flat light conditions. All lenses provide 100% protection from harmful UVA/B/C rays.