KOOLSUN's innovative range of sunglasseses have the best possible fit for babies and kids with a frame that is completely FLEX(ible). These extremely durable sunglasses means parents no longer need to worry about their child accidentally breaking their glasses. In addition, the silver mirror lenses are made of strong polycarbonate that cannot break. The lenses are certified optical class 1 and cat. 3, useful in blocking harmful UV-A and UV-B radiation 100% guaranteed.