Iron Halo (5e Equipment)

Armor (Shield), very rare (requires attunement)

A small circular device that can be held in a single hand, an iron halo projects a field of magical force to repel attacks.

Force Projection. As an action, you may increase the density of the iron halo's protection field. You gain a damage threshold equal to your proficiency bonus for 1 minute. You must concentrate on this effect as if it were a spell. When you use this feature, you may increase this damage threshold by 1 for every 100 gp spent to a maximum total damage reduction of twice your proficiency bonus.