Like all La Vaule (S) NM Level 69 Weapons, you'll need the Supremacy Earring to get the full "Set:" effect. The earring drops from the BCNM that is granted access if you defeat all 8 NMs in La Vaule and trade the 100% StrongBox items in to a NPC Named Lurouillat in Southern San d'Oria (S).
Those items also benefit San d'Oria in Campaign. Look up the quest called "Sealed Containers."
