A red dot sight is a commonly known as a type of non-magnifying reflector (or reflex) sight for firearms that gives the user an aim-point in the form of an illuminated red dot. Red dot sights are typically not magnified and are for use on pistols, shotguns, even bows, and are for short range or close quarters work. Its aiming style is different from Laser sight, laser sight is not the dot  but straight laser light line shot directly on the objective, the laser light line can be seen throught outside the scope, but the red dot from the red dot sight only can be found inside the scope view.

 

It's perfect for the people who love to play paintball! To properly use a red dot, both eyes must be kept open. You ignore the view of the scope. Don’t look into it.Look past it or beyond it. Pretend it is not there.

 

Once you get the hang of it, your red dot will not limit your field of view in the slightest. Your brain superimposes the image that one eye is seeing through the sight and there is just a red dot "floating in the air" in your normal full field of view that both eyes are seeing. Because both eyes are open, you probably have a 280 degree field of view. Very quick target acquisition is possible. Just move the marker to put the dot over what you are seeing. If it is adjusted properly, your paintballs will hit whatever that red dot is floating in front of.