This necklace displays the classic S shield symbol in ultra high quality 316 stainless steel. Not entirely sure what those numbers correlate to but it does mean that the stainless steel is of an exceptionally high grade! A chrome like sheen and durability, just like the man of steel! This Superman Red Symbol Stainless Steel Necklace stands 1 inch high and 1.25 inches wide...a perfect blend of subtlety and color!