Armour of Invulnerability

Armour (plate) (requires attunement)

Rarity: Legendary

You have resistance to nonmagical damage while you wear this armour. Additionally, you can use an action to make yourself immune to nonmagical damage for 10 minutes or until you are no longer wearing the armour. Once this special action is used, it can’t be used again until the next dawn.

Source: Player’s Handbook