Arcane Crystal of Defense, +1

Arcane Crystals are a further refinement of an Arcane Focus, serving to help the wielder amplify a particular aspect of the magical power they channel. Arcane Crystals do not require an attunement slot, but you can only equip a maximum of one Arcane Crystal equipped at any one time.

When you cast a spell, you gain 1d6 temporary hit points, up to a maximum of 10.