Bards Gilded Amplifier

A delicate device made of silver with tiny twisting silver vines curling outwards, and a small clip on the backside of it. 

When attached to a bards instrument of choice their music spreads farther and louder, protecting their companions from potential harm.

As a reaction when an ally you can see is hit by an attack you can expend a use of a bardic inspiration die to boost their AC, potentially turning a hit into a miss.