The brightness of a work light or headlight in lumens is only a theoretical value that does not take into account losses that occur. The concept of effective lumens provides a remedy. In contrast to theoretical lumens, these take into account all relevant losses and thus indicate the actual light output of a light.
To be able to measure this value, a rather complex and cost-intensive photometry is required. Many manufacturers shy away from the costs here and content themselves with naming the theoretical light output. However, this is exactly what makes it very difficult to compare lights from different manufacturers and means that you do not always know how much light you are actually getting. All lumen specifications for our products are to be regarded as effective lumens.