To the best of my knowledge, this is the ONLY piece of equipment that someone can use to raise somebody else. This includes all special event gear, items, and all weapons/armor.
You don't need to know the spell raise, you can cast on people outside your party.
If you don't have this item, I would highly recommend getting it. The best way to do this is either during Feast of Swords, or by winning Rank 3 in the mog bonanza (get the last digit correct) by trading the winning pearl for a Kupon AW-COS.
If you have an army of mules, you CAN trade the hat to other characters on the same account. So in theory, if you subscribe for a total of 9 extra characters, pick your own bonanza numbers so they end in 0,1,2,3 etc., you are guaranteed the hat.
New Feast of Swords item for 2015.
It's a pretty phoenix inspired Kabuto helm. (Can't *imagine* why the phoenix imagery... *cough*RhapsodiesofVana'diel*cough*)