I needed to go outside for just a moment. I live on many Acres. I just reached in the "junk" drawer since it was only going to be for less than 5 minutes. I was surprised how dim this light was. Turns out it was a SF L1! Of course than I tested the batteries and they were nearly full. It is strange to think that light was once state of the art! Ahh, nostalgia. To look at it another way, it is still probably brighter than a Mag 4D LOL For that matter I now use a L4 to work inside computers. I guess lights and our expectations have greatly increased in really not that long a time. This technology has moved very fast. I do not doubt eventually there will be 50,000 Lumen lights that run 3 hours on primaries.