This is the "HQ" version of the Return Ring, gained from the same event. I posted pictures and details of both on the main forum but I guess it just got ignored.
Still, the Return Ring is the other event-only item gained from the adventurer appreciation event. It is the same with only 10 charges. Below is my pic of it. Again.
http://i2.photobucket.com/albums/y38/mikaga/ffxi/returnring.png
Fyrecow almost had it right: These rings move you to the outpost of the region you're in. However, they work *regardless* of who controls the region, or even if the beastmen do.
Also, you do not need to have done a supply quest to the region. This makes the rings good for completing supply quests too - get the quest, enter the region, use the ring, complete the quest, outpost warp home.
I value these rings very highly, both because they are very useful and because they took me so long to get. The event wasn't easy, as it involved finding other people willing to move around the world for what'd likely get them two chocobo tickets.
Edited, Fri Jul 15 09:36:46 2005