Refinements:

For every party member from Natlan or who has a different Elemental Type from the equipping character, the equipping character gains 4.8%/6%/7.2%/8.4%/9.6% increased ATK. When there are no less than 3 of the aforementioned characters, the equipping character gains 24/30/36/42/48 Elemental Mastery.