A red dot sight (also called a reflex sight or, for certain models, a reflex scope) is a non-magnifyingfirearmsight that uses an illuminated reticle, typically in the form of a red dot.
Most red dot sights have either active or passive adjustments for the dot brightness, allowing a very bright dot for high visibility in bright conditions, and a very dim dot to prevent loss of night vision in low light conditions.
Since dot sights can be mounted at any distance from the shooter's eye with no issues of focus, military rifle mounts usually place the sight in any mechanically-convenient mounting position, such as the carrying handle of the M16 rifle, or on a rail system (typically a Picatinny rail) on top of the rifle. This leaves plenty of room for night vision equipment to be used with the red dot sight.
