Adamantine Armor

Armor (Any Medium or Heavy, Except Hide Armor), uncommon

This suit of armor is reinforced with adamantine, one of the hardest substances in existence. While you're wearing it, any Critical Hit against you becomes a normal hit.

Adamantine Armor is from the System Reference Document 5.2.1 (“SRD 5.2.1”) by Wizards of the Coast LLC, used under the Creative Commons Attribution 4.0 International License. Full attribution is on the Licenses & Attribution page.