It is eyewear accessory of eyeglasses frames. Protect the optical frame to avoid out of shape. AC of Copolymer will be never cracking for rimless frame. 1) Diameter: 55mm, 60mm, 65mm, 70mm, 75mm, 80mm 2) Thickness: 1.0mm, 1.3mm, 2.0mm, 2.3mm, 2.5mm, 3.0mm 3) Base:300, 400, 500, 600, 800, 900, 1000 4) Un coating or Hard coating or Hard multi coating(AR coating) 5) AR-coating: red, green, blue, ...