Saint Laurent SL 224 is a Full Rim, Progressive Eligible frame for Men, which is made of Acetate & Metal. Most metal frames are made out of Monel. Monel has a copper and nickel base and is one of the most commonly used metals for frame manufacturing. This metal can be corrosion resistant, strong, and easily adjusted. It retains its stability and shapes for long periods of time. ----- Acetate is the most common material used for frame manufacturing. It has endless possibilities for color, texture, and patterns. It can even be laminated to create great visual effects, and it can retain a higher luster. Acetate is lightweight, so it is often chosen for its versatility in coloring as well as for its comfort. Acetate is made out of cotton seed fibers and plasticizers.