A lot of detective oriented television series showcase a range of new gadgets and props from the fancy multi utility cars in a certain flamboyant British secret agent movie to the primitive tools of the global phenomena familiar in the name of Sherlock Holmes. Interestingly enough, from the Victorian times of Sir A.C Doyle to the post modern description of a detective, a flashlight has always manifested itself as being one of the key ingredients of a dark alley climax.
Investigative use of military flashlight:
Depiction within fiction, essentially, is a humble extension of reality and the military tactical flashlight strapped onto the law enforcing agents to aid their purpose of aiming a shot in a considerably dark environment is an actual tactic implemented and fairly taught for cases of confrontation in areas where there is a lack of natural light taking into account the time of the day and the geographical location.
It is fair to comment that a military grade flashlight and its subsequent attributes are not only employable by law enforcement agents in cases of combat but are also adequately able to deal with the complications of much finer importance especially in cases of archaeology and safety investigations.
An example of that would present itself while inspecting the layer of ice on the wings of an aircraft by the ground crew and letting the pilots know for the purpose of determining whether the said plane would be capable of maintaining its required aerodynamic equilibrium while it is flying.
The optical principle used in military flashlights is the reason that it finds itself as a useful commodity across various fields especially when the projection of parallel rays of light is concerned thus enabling minimum deviation and effecting maximum intensity to focus on the subject being inspected or sought.