The Rio is an ultra-modern round lens-shaped style, but what makes it even more trendy is that the lens is made out of one piece, including the bridge. The legs are made of walnut wood. The front is made of polycarbonate. We use outward flexible metal hinges for a flexible and comfortable fit. All GOWOOD sunglasses provide real protection with their FDA approved and CE certified category 3 high-quality lenses. They are impact-resistant and are provided with a hardwood bamboo storage box.