If you like camping, hiking or any other outdoor activity you better be prepared to have a good source of light with you. When the sun light begins to fade a good LED flashlight is the best option to choose. The strength of a LED flashlight is defined by the quantity of Lumens emitted. To better evaluate the range of application LED flashlights are classified by their quantity of Lumens. But first let us take look at the unit Lumen. Lumen is the unit of the Luminous Flux. It is derived from the Luminous Intensity. By definition Lumen is the product of the solid angle and the Luminous Intensity. In other words Lumen is a measure for the quantity of light that can be seen by the human eye emitted by a source. LED flashlights with an output up to twenty-five Lumens can be used for reading and walking in twilight. The next class ranges up to an output of one hundred Lumens. These LED flashlights are suitable for general outdoor use. If you need a search light for longer distances you be well served with the next class. The range is up to 999 Lumens. But there is even a higher class. That are LED flashlights with a minimum output of 1.000 Lumens. This is the strongest class of LED flashlights. These LED flashlights are well suitable for professional use. For example if you want to do caving there is no way around a flashlight with more than one thousand Lumens.