Magic Defense Plus %

Magic Defense Plus %, otherwise known as Spirit Plus %, is a recurring support ability in the series. It first debuted in Final Fantasy VIII, and generally boosts a user's Magic Defense by a certain percentage ranging anywhere between 3% to 60%, to a cumulative maximum of 100%.

Final Fantasy VIII
Spr +20%, +40%, and +60% must be equipped beforehand in order to use their effects. Spr +20% and +40% can be learned through the GFs Shiva, Alexander, and Leviathan, and also through the items Rune Armlet and Force Armlet, while Spr +60% must be learned through using a Magic Armlet.

Final Fantasy X
Magic Defense +3%, +5%, +10%, and +20% can be found on dropped armor or by customizing them onto armor by using 3 Mana Sphere, 2 Mana Spring, 1 White Magic Sphere, and 4 Blessed Gems respectively.