A tactical light is a flashlight used in conjunction with a firearm to aid low-light target identification, allowing the marksman to simultaneously aim and illuminate the target. Tactical lights can be handheld or mounted to the weapon with the light beam parallel to the bore. Tactical lights also serve a role as a method of non-lethal force, used to temporarily blind and disorient targets. Features particularly associated with tactical lights include shock resistance, reliability, lightweight and powerful batteries, and high light intensity. Tactical lights may have optional filters to produce colored light, or may emit only infrared radiation for use with night vision equipment. A sighting laser may also be added to a weapon-mounted tactical light.
Handheld lights are generally restricted to use with handguns, as long guns require two hands to operate. While just about any handheld flashlight can serve in the role of tactical light with the proper technique, some features are more readily adapted to the role. Some manufacturers sell lights specifically designed for use as handheld tactical lights. Police training programs in shooting while holding a flashlight date back to at least the 1930s.
To use a handheld light as a tactical light, the handgun is held in one hand, and the light in the other. There are a variety of positions that can be used to allow the light and handgun to be held parallel and provide mutual support, or the light can be held off to the side of the body to present a false target to a potential assailant. Since the weapon and light are not attached to each other, the light may be used to illuminate areas that may or may not contain a target, without pointing the weapon at the area. If a target is detected, the handgun can quickly be brought into line to cover the target.
A flashlight intended to be used in this way will have provisions for ease of use when used with a handgun. Some models will have a narrow body and a ring designed to fit through the fingers, allowing the light to be used in a tight two handed grip on a handgun, with the switch controlled by pulling back with the fingers on the ring. More traditional models can be used as well. Some flashlights feature a momentary on switch so that the light is quickly turned off by releasing finger pressure on the button. Another useful feature is the ability to attach a lanyard to the light, allowing the light to be secured to the hand holding it; this allows the light to be dropped if the hand is needed (for a magazine change, for example) and quickly retrieved.