Armor of Resistance

This armor grants you resistance to one type of damage. The type of damage is determined when the armor is created, from the following list: acid, cold, fire, force, lightning, necrotic, poison, psychic, radiant, thunder. A suit of light or medium _armor of resistance_ is rare, and a heavy suit is very rare.

Source: Level Up Advanced 5e · OGL-1.0a · 5.1