Here is the basics on navigational lights. As oldtexan I am a firm supporter of lots of good qualified training.

In simple terms, the reason for navigational lights is to be able to illuminate an area and have enough light to identify objects & people without having your pupil’s contract. They are designed to be used on a pistol with a handheld bright white light as backup. While using the blue or red led lights to move around in near to total darkness your pupils are in the dialated stage and are adjusted to the ambient light. If you should turn off the light for any reason as to hide and listen for signs of someone moving around your pupils are already at the night vision, (dialated) level. If you were using a bright white light to look around and you turned it off it will take a few seconds to a few minutes for your eyes to re-adjust to the surrounding darkness. By using a soft dim light to navigate around your are able to see in the dark & in event the navigational light is turned off you night vision will not impaired.
These are not new in the law enforcement field. Surefire has had them for years on the M900V vertical pistol grip for AR15 format. They are new in the pistol industry.
The small led’s are designed for CQC type scenarios, like moving around & clearing a house. Not for the longer distances of a large warehouse or outside. This is the reason for having a larger bright flashlight in your off-hand.
A standard bright light has approximately 100-170 lumens. When turned on to illuminate a subject you will have an instant blinding effect on that person. Depending on the intensity of the light, it will momentarily activate all light sensitive cells in the eye, making vision impaired or impossible to see for a few seconds to a few minutes until the eye restores itself to its normal state. In the same instant, you being behind the light, also will have diminishing vision due the same blinding effect, although in less amounts because you are not in the direct line of the intense beam.

Hope this explains the reason and theory behind navigational lights.

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TDR911 Sigma Laser Systems