Adapts to a wide range of plastic and metal eyeglass frames. Patented, unique design allows quick and easy installation without tools. Molded from impact resistant polycarbonate for excellent protection. Impact tested to ANSI Z87 specifications on both metal and plastic frames. Complies with DOL, OSHA Rule 29 CFR Part 1910.133. Exclusive UVS additive provides an ultraviolet barrier for protection against harmful UV radiation.