PDLC, or Polymer Dispersed Liquid Crystal displays, is a technology that allows glass to switch between clear and opaque states with the flip of a switch. It operates at 3-5V and has a contrast ratio of 40:1. Unlike other displays, it does not require further reductions in voltage or temperature. However, it currently cannot display colors like LCD. When switched to the opaque state, the glass becomes foggy and prevents seeing through it.