Adapting to light conditions without you even noticing, the Gul Petrel Goggles are ready to make a splash in the open water. Designed with photochromatic technology, the lens darken when exposed to ultraviolet rays from sunlight and then fade back when the UV light diminishes. \\\"Photochromatic\\\" clarity helps to aid sighting, allowing you to move around obstacles and other swimmers easily. Created to fit your face perfectly, a combination of different density silicon and TPR help to create a perfect seal and prevent any unwanted water leakage. Key features photochromatic technology adapts to different light conditions easily adjustable strap for the perfect fit storage case provided