Heavy Armor Expert Feat

You master the use of heavy armor, using it to turn aside blows and reduce damage taken. You gain the following benefits:

Prerequisite: Proficiency with heavy armor

• Ability Score Increase. Increase your Strength or Constitution score by 1, to a maximum of 20.
• Damage Resistance. While you are wearing heavy armor, bludgeoning, piercing, and slashing damage that you take from nonmagical attacks is reduced by your proficiency bonus. If the heavy armor is magical, it reduces damage from all sources besides the Psychic damage type instead.

Source: KT