Wondrous Item, rare (requires attunement by a Two Hours attunement )
While wearing the amulet you can cast the spell mage armor, if the amulet is one armor the enchantment will not work the spell lasts till the character dismiss the spell or dons on armor. The target's base AC becomes 13 + its Dexterity modifier. The spell ends if the target dons armor or if you dismiss the spell as an action after you dismiss the spell you will not be able to use it till the next day.
Notes: Two Hours attunement