Bracelet of the Shattered Aegis

A smoldering, defensive insignia burns at the center of the cracked glass sphere that rests atop this woven bracelet. The bracelet has 2 charges and regains all expended charges daily at dawn. If the bracelet has at least 1 charge, you gain a +1 bonus to AC while wearing it.

While wearing the bracelet, you can expend 1 of its charges as a reaction when a friendly creature that you can see within 30 feet of you is hit by an attack. That creature gains a bonus to its AC equal to your spellcasting ability modifier (minimum +1) until the start of your next turn, including against the triggering attack, as a shimmering, magical barrier protects it from harm. If the creature is already under the effect of the shield spell, this property has no effect, and the charge is wasted. If an attacker hits the creature while it's protected by this barrier, the barrier shatters, and any hostile creature within 5 feet of it must make a Dexterity saving throw against your spell save DC. On a failed save, a creature takes 3d8 fire damage, or half as much damage on a successful one. When the barrier shatters, the creature loses this bonus to its AC.