A piece of hardware which enables the wearer to see in the dark. Nightvision goggles are an invention of the US Military, but are now available on the civilian market. There are two main types: infra-red and light-amplification goggles. The former use an infra-red beam, invisible to the naked eye, to iluminate the subject or target. The infra-red light bounces back and is picked up by the goggles. The latter amplify the ambient light in any given scene, making them more effective and more expensive.