These black & gold pilot sunglasses have photochromatic lenses that adapt to sunlight (UV light sensitive). Depending on the UV index, the lenses darken up to 50% from the original lens translucence. The lenses are high-quality polarizing TAC lenses with clear HD vision and complete UV400 protection. A stainless steel frame with an adjustable spring hinge completes the excellent user experience and adds a lot to the durability of the photochromic pilot sunglasses. Great, comfortable sunglasses for driving long distances or for daily go-to sunglasses.