Mox Opal

This unbroken loop of highly polished steel has a matching medallion hanging from it, at the center of which sits a triangular opal, sparkling with a thousand dazzling colors. As long as you are attuned to three more more magic items other than the mox opal, while you are holding or wearing it you can use an action to cast any spell of 5th level or lower, without requiring material components. When you cast a spell with the mox opal, the spell attack bonus is +10, and the spell save DC is 18. In addition, while attuned to the mox opal, you can become attuned to any number of magic items. If your attunement to the opal is broken for any reason, you automatically lose your attunement to all other magic items as well.