This is a Parker ballpoint pen I received from my uncle. It appears to be a special edition vintage ballpoint pen, with 13 diamonds embedded in the clip. The diamonds were confirmed by a tester (or similar device) when I took it to a buyer. The ballpoint pen itself is engraved with "Parker" and "MADE IN USA," as well as "AI." I researched this and found the following information: ◆【Special Order Models for Japan (Anniversary Issue and Artistic Issue)】 • "AI" is an abbreviation for "Anniversary Issue" or "Artistic Issue," and is sometimes used for special edition limited editions and gift models. • It can be found on commemorative items for companies and organizations, or on diamond-decorated models specially ordered by Parker's authorized dealers. I am not an expert, so I will not be able to answer any questions. Thank you for your understanding. Thank you for looking.