The "Sphere" effect is apparently a constant buff generated by the wearer given to nearby allies. Armed with that Knowledge, this piece is likely best used by a supporting job (Bard or Summoner) to enhance a black mage, scholar or red mage's offensive nuking power.
not sure why no one has mentioned this, but this body has 10% fast cast, coupled with the 12 enhancing magic, its a must have for enhancing magic skill based spells and precasting just about everything. to my knowledge for every job but rdm this is the only body that has 10% fast cast for the jobs listed.
Actually, this comes from the T4 Voidwatch NM Celaeno in Dangruf Wadi. If you check the synthesis materials for the synthed versions of this body as well, they also require Celaeno's Cloth.