"Proto" series The series is named Proto, which means "early" or "prototype". Signet rings are said to have the oldest historical background in jewelry. Originally, a round or square pedestal with a family crest carved out was called a signet ring and was worn on the little finger of the left hand. A thinner ring of the "Proto" signet ring, which is a sharp and simple signet ring. The sharp production that minimizes waste is kept as it is, leading to a healthier atmosphere. It has a gender-neutral design and is recommended as a pairing. The ring is made of high-quality material with SILVER925 (sterling silver) and K18 coating.