Dragon Apxs Gigi Ruff goggles Interchangeable lens design makes it easy to swap lenses to meet the conditionssimply pop the existing lens off of the frame and snap in the replacement lens Oversized spherical lens tapers from the optical center toward the periphery for an extra-wide field of vision with minimal distortion Double-layer lens creates a thermal barrier between the cold outside air and the warm air around your face, helping reduce fogging