Adamantine Plate Armor of Undead Fortitude

Armor of Undead Fortitude
If damage reduces you to 0 hit points while wearing this armor, you can make a Constitution saving throw, unless the damage is radiant or from a critical hit. The DC for this saving throw equals 5 plus the damage you took. On a successful save, you drop to 1 hit point instead.

Adamantine Reinforcement
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.

Plate consists of shaped, interlocking metal plates to cover the entire body. A suit of plate includes gauntlets, heavy leather boots, a visored helmet, and thick layers of padding underneath the armor. Buckles and straps distribute the weight over the body.

Notes: Str. 15 Required, Stealth Disadvantage