Anti-Charm Earpiece

An intricate earpiece made of many tiny, copper gears and pistons. The earpiece can adjust for kinetic forces using a built-in gyroscope, making it very difficult to remove by accident. As a reaction, the wearer can tap a button on the earpiece, causing it to produce a shimmering hard-light helmet around their head. Until the end of their next turn, the wearer has advantage on saving throws against being charmed and cannot be targeted by mass charm effects.