The Hitchhiker's Guide Project

Peril Sensitive Sunglasses

Joo Janta 200 Super-Chromatic Peril Sensitive Sunglasses have been specially designed to help people develop a relaxed attitude to danger. At the first hint of trouble, they turn totally black and thus prevent you from seeing anything that might alarm you.

A double-pair is frequently worn by Zaphod Beeblebrox.