Earpiece

He wore an earpiece.

The bodyguard was wearing an earpiece.

He wore an earpiece so that she would guide him.

There was a series of clicks and buzzes in the earpiece then Zack heard a man's deep voice.

At the end of my work day, I remove my name tag and earpiece and leave them in my locker.

Holonym: headpiece (sometimes holonymous)

Holding the earpiece to my ear, I could hear him speaking clearly.

My glasses won't stay on, as I've broken the left earpiece.