3-1/2" long .925 quality marking stamp for sterling silver. A "quality mark" is the little number or letters that indicate what metal and purity is used in an item made of a precious metal. By law, this stamp can only be used to mark an item that is made from .925 sterling silver. Argentium is sterling silver and can be marked ".925". The bent stamp has the advantage of fitting inside of a ring shank to mark rings as well as other items.