The versatile Oakley Half Jacket Sunglasses Activated by Transitions feature lenses that lighten and darken automatically, depending on light conditions. Whether you trail run at dawn, mountain bike as clouds roll in, or stroll to lunch under the noonday sun, these sunglasses transition, so theyre neither too dark nor too light. The Half Jacket Sunglasses also feature an interchangeable lens system, so you can swap out lenses when you please. The lightweight, durable open-edge frame feels comfortable all day. The grippy arm and nose pads mean your glasses stay on your face as you bike, hike, or just enjoy the sun. Additional lenses are sold separately.