A masterwork suit of armor or shield.

In general, magic armor protects the wearer to a greater extent than nonmagical armor. Magic armor bonuses are enhancement bonuses, never rise above +5, and stack with regular armor bonuses (and with shield and magic shield bonuses). All magic armor is also masterwork armor, reducing armor check penalties by 1.
Shield enhancement bonuses do not act as attack or damage bonuses when the shield is used in a bash.
+3 enhancement bonus adds 6 to a shield's hardness and +30 to its hit points.

Prerequisites: Craft Magic Arms and Armor.
Cost to Create: 4,500 gp (plus 150 gp for base item), 360 XP, 9 days.