Wellshaft Hoop

This broad iron earring carries a single clear glass bead suspended from a short chain. A perfect drop of water hangs motionless inside the bead, never evaporating or touching the glass, though it trembles faintly when held over deep places.

While the wearer stands over a shaft, well, or drain, they hear everything at the bottom of it to a depth of 200 feet as clearly as if they were standing down there.