What does the stamp OB on inside of a ring mean?

The stamp "OB" inside a ring typically indicates the manufacturer or designer of the piece, with "OB" often representing a specific jewelry brand or artisan. It may also signify that the ring is made from a specific metal or alloy, as some jewelers include their initials or brand mark as part of their quality assurance. To get a precise meaning, it's best to consult resources or experts specific to the jewelry industry or the brand in question.