All night vision products work pretty much the same way - they turn light that isn't visible to our eyes into something we can see.

Here's a quick description of how it's done:

• Light from all bandwidths (visible and invisible) is gathered by the front objective lens.
• After passing through the lens, the light enters an electron intensifier tube where is hits an electrically charged wall.
• When the light collides with the wall electrons get knocked off like little ping pong balls. These go on to smash into a phosphorescent screen, similar to your TV.
• The result of all this smashing and crashing is a green glowing image. When you look into your night vision unit, that's what you see - a beautiful, monochrome green night vision image.

What's really intriguing about all this is that no matter how dark it is, there's usually plenty of available light. You just can't see it - unless you've got night vision of course!