A cube that floats around a person and provides defense. Made of iron and silver it’s inlaid with runes of defense and protection. They are made to especially provide defense against mages.

 When equipped gain +1 to AC

it has 3 charges that regenerate on a long rest. You can spend a charge to cast shield as a reaction. You can use two charges to cast counterspell as a reaction or use all the charges to cast dispel magic as an action 

Trapped 

inside a lead box there is a bomb. It take a DC 30 intelligence check to find and disarm the explosive, magic can’t be used to help. The bomb will activate when the right signal is given dealing 2d10 force damage 

Notes: Bonus: Armor Class