At 2nd level when you select this arcane tradition, you learn the spell mage armor and add it to your spellbook. Additionally when you cast it on yourself or on your familiar, should you have one via the spell find familiar, the spell sets the target's base AC to 18 instead of 13 + its Dexterity modifier.

Enhanced Range

Also beginning at 2nd level when you are either wearing heavy armor or have cast mage armor on yourself, you can choose to reduce your movement speed to 0 at the beginning of your turn. This lasts until the beginning of your next turn. When you reduce your movement speed through this feature, you double the range of any spell you cast that has a range of over 5 feet, and any spell that has a range of 5 feet instead has a range of 15 feet.

This increases at 14th level so that the range of any spell you cast that normally has a range of over 5 feet has its range tripled, while any spell you cast that normally has a range of 5 feet instead has a range of 90 feet.