Helmet of Arcane Acuity
Dexterity Saving Throws +1
Location - Helmet of Arcane Acuity
Act 2. The helmet is located in Reithwin Town, Masons Guild Basement:
You will find a trapdoor at the far end of the building.
You can also use an elevator on the outside of the building. Once inside, search around the room, as you will get a Perception check, this will reveal Keyhold Herald, which you can either lockpick or use a Tower-Shaped Key. The key can be found in Last Light Inn, purchased from Mattis, or looted from a bag in the inn if he died.
The helmet can be looted from a chest in the main room. There will be a combat encounter with some shades.
This helmet is almost mandatory to get. It is one of the main items for Gish or Spellsowrd type builds, together with the Band of the Mystic Scoundrel. This allows to increase Arcane Acuity, via normal attacks, which then boosts spell success chance, covering the problems of low Spell Save DC.