What does 10k ddb mean when its on the inside of a ring?

The inscription "10k DDB" on the inside of a ring indicates that the metal is 10 karat gold, which means it contains 41.7% gold and the rest is made up of other metals. The "DDB" could signify the manufacturer's initials or a specific design or collection name associated with the ring. This marking helps identify the quality and authenticity of the ring's material.