This proprietary lens tint from Giro has a multi-layer coating that increases detail and depth perception in lower lighting conditions. With a visible light transmission (VLT) percentage of 50-60%, this lens is perfect for those cloudy days when the sun is nowhere to be seen. VLT refers to the amount of light from the visible spectrum that is allowed to pass through an optical lens, such as a snow goggle. The range given for this goggle lens reflects differences between spherical and cylindrical versions.