The sights were designed with the intent to allow you to perform at your maximum level while under stress.
These sights are able to be utilized in low light situations. The Big Dot front sight has a tritium insert in the middle of the sight. Additionally, the rear sight has a vertical tritium vital insert. These tritium inserts provide you with glowing green aiming reference when there is not enough ambient light to properly see your sights.
The tritium used in these sights is a radioactive material that is self-illuminating. The tritium does not rely on external sources to help it to illuminate. This means that this lighting source is extremely reliable and will be able to provide you with a glowing aiming point in near all conditions.
The designers at XS sight systems had the goal of developing a sight that was easy to rapidly acquire and could be used in times of extreme stress. The Big Dot and V-Notch sight picture was developed after extensive research and user feedback. Many user have found the XS big dot sights capable of doing just that. The Big Dot front sight is easy to track and pick-up during the draw.