This is a super cool and relatively rare FD usually matched with the RD-5900 rear derailleur of the same name. These are uncommon due to the short time they were sold and the quick introduction of the Mountech in succession (essentially the same derailleur with less fluff). Date code is ZG which means this derailleur was manufactured in July of 1984. This is one of the best reverse pull triple FDs ATMO.