It would not make any sense to use 100 percent of the maximum brightness during the entire run time until the batteries are discharged. That wouldn’t take very long. Therefore, the Walther Pro Lights start with maximum brightness, but then reduce it to a lower level in order to increase the run time. However, this reduction of brightness presents no problems, because the human eye works very well with a limited amount of light in darkness, whereby various photoreceptors quickly adjust to different lighting conditions. Apart from that, too much light is often neither necessary nor sensible. If maximum brightness is required again, the lamp only needs to be switched off and back on. Full brightness is then immediately available again.