Google is my friend. According to what I found, WMF 90 is silver-plate. The 9 in the box refers to grams of silver used.

What does 90 mean on silverware?

If you have a sugar tong marked 90 and 2 it means: again the standard process was used, 2 Grams of fine silver were used to coat the piece. If you have a pair of salad servers, each piece marked 90 and 4 it means: again the standard process was used, on each piece 4 Grams of fine silver were used.

What are the markings for real silver?

American sterling silver is marked with one of the following hallmarks: “925,” “. 925,” or “S925.” the 925 indicates that the piece contains 92.5% silver and 7.5% other metals.

Is WMF a good brand?

Today, WMF is one of the most recognized names in German cookware, with a full line of kitchen accruement including pots and pans, bakeware, cutlery, kitchen gadgets, and more. Pricing tends to be mid-range, which makes the brand financially accessible while still retaining their outstanding reputation.