The clip-on or stud H1 Audio Earrings from Nova Audio feature two speakers behind both pearls (which are real, by the way) that use directional sound to transmit audio up and into your ears.
Nova says the technology adds “a layer of sound” to your environment, allowing you to hear what’s going on around you while still enjoying your audio, similar to Sony’s open-style LinkBuds or Aftershokz’s bone-conduction headphones.
Source: theverge.com