The Nike ACG Vista Peak PH (Photochromic) sunglasses are designed for trail runners who don't mind rapidly changing light. The half-frame design ensures lightweight and a wide field of vision, while the photochromic lens reacts to the intensity of UV rays, darkening in full sun and instantly lightening when the trail enters the undergrowth. The ideal adventure companion for maintaining a steady pace from dawn to dusk, ensuring perfect vision on any type of terrain.