The Joo Janta 200 Super-Chromatic Peril Sensitive Sunglasses have been designed to help people develop a relaxed attitude to danger. They follow the principle "what you don't know can't hurt you" and turn completely dark and opaque at the first sign of danger. This prevents you from seeing anything that might alarm you. This does, however, mean that you see absolutely nothing, including where you're going.
It also tells you that there is something that would alarm you, could you see it. This information alone could potentially alarm you.
The Joo Janta 200 Super-Chromatic Peril Sensitive Sunglasses appear in:
- Episode 3 of the television series.
- Chapters 5 and 6 of The Restaurant at the End of the Universe.
- Episode 1 of the Hexagonal Phase radio series.
- A merchandise version of these sunglasses was included with the purchase of The Hitchhiker's Guide to the Galaxy video game.