What is an Image Intensifier Tube (IIT)?
An IIT is a module that intensifies, or amplifies, low light level images into levels that can be seen by the human eye. The IIT collects the existing ambient light from natural sources, such as starlight or moonlight, or from artificial sources such as street lights or infrared illuminators. The light passes through several internal components to be multiplied several thousand times, producing a much brighter image that can be seen by the soldier through the night vision device.