610 CLIP-ON Eyeglasses by Flexon. The rectangle shape design feature a full rim metal frame. This model is available in nine different color combinations and sizes. Flexon sets the new standard in flexible and durable eyewear with its technologically advanced collection of eyeglasses. Each frame is carefully crafted from cutting-edge materials, such as Flexon Memory Metal, TR-90, Beta Titanium, top-grade Rubber and Stainless Steel, in order to be lightweight, extremely strong, easy-to-wear and compatible with progressive lenses. Featuring an ultra-flexible construction, the frames are sure to return to their initial shape after being bent, flexed, or twisted.