The Flip RX are half-rim Prescription Sports Glasses with flip-up lens system. The Flip RX have an interchangeable lens feature for all light conditions. Its RX Insert allows for powers up to + or – 4. The Flip RX has been design to allow for lens filter to be removed from your vision in a second. Imagine you are cycling or running and a cloud comes over resulting in poor light levels without having to struggle to with reduced vision, you simply flip the filter out of vision. They are fitted with rubber nose pads and rubber arm inserts for grip and comfort. This product has been designed with range of sports in mind, such as Cycling, Running, Skiing, Driving, Hiking, Golf and general sports use.