Typically, tactical flashlights serve additional purposes beyond just acting as a flashlight. A tactical flashlight can be used for self-defense purposes and, if need be, as a weapon. Tactical flashlights tend to be dense, yet still lightweight enough to be carried comfortably and without user fatigue. This largely depends on the materials used to make the flashlight, such as reinforced, anodized aluminum alloy.
A tactical flashlight must also be completely reliable, as they are relied upon in emergency situations. That is why flashlights are key components of survival and emergency preparedness kits. They must be corrosion and rust-resistant, weather-resistant, moisture resistant, and rated to withstand a drop of at least one meter without breaking or cracking.
Tactical flashlights also tend to be brighter than utility flashlights. As a rule of thumb, a utility flashlight should have a maximum lumen output of no less than 200 lumens. This is adequate light to illuminate a football field, and to see an object at a distance of 50 feet away with perfect clarity. Also, tactical flashlights serve other purposes. For example, many have serrated edges. This allows you to dig with the flashlight, use it as a multi-tool, shatter a windshield or window, or hit an attacker.
If you do intend to use a tactical flashlight as a self-defense tool, there are some advantages to doing so. It is not considered a lethal weapon. It is legal to carry a tactical flashlight in all 50 states. The serrated edge is extremely helpful if you are the victim of an attack. While this is certainly not the primary purpose of a flashlight, in an emergency, it can be your first line of defense against an attack.