In simple terms, Lumens (denoted by lm) are a measure of the total amount of visible light (to the human eye) from a lamp or light source. The higher the lumen rating the “brighter” the lamp or torch will appear allowing you to see further in the dark.
A single lumen is equivalent to around the same light output as a standard lit candle.
As a general rule, the higher the lumen output, the more power it will use. Many of our lights such as our range of Nebo head torches have different lumen settings in order to prioritise power and the amount of light for different situations.