Elemental Affinity was part of the Armor 2.0 rework that came to Destiny 2 back in late 2019. Armor pieces (helm, chest, arms, legs, and class item) now have an element associated with them (Solar, Arc, Void, Stasis), and this determines the types of mods that can be slotted into that piece of armor.
In the beginning, this selection was very limited, with specific weapon mods being available for certain elements. It was a headache, and there was little rhyme or reason as to what could be slotted in each piece of armor.
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Void
Solar
Since then, Bungie has revised Elemental Affinity and added Stasis as a fourth option. Guardians are now able to swap a piece of armor to a different element for a price. The cost is determined by the number of upgrades in place on the piece of armor. This went into effect with the Beyond Light expansion.
Stasis
For more Destiny 2 goodies, check outWhat is the Weekly Nightfall Weapon in Destiny 2? (March 15 to 22)on Pro Game Guides.
