Armor Mastery

You become more maneuverable while wearing armor. You can move at your normal speed in medium armor that is made of metal. This does not grant proficiency in armor. At 5th level, whenever you are wearing metal armor, you reduce the armor check penalty by 1 (to a minimum of 0) and increase the maximum Dexterity bonus allowed by your armor by 1. At 10th level, and again at 15th level, these bonuses increase by 1.