I used them to tag my team's backpacks during the nighttime search and rescue this weekend and they were bright as hell. We ended up covering them up a bit to reduce light pollution and preserve our natural night vision in the forest when searching. We also used them to mark our hasty shelter so the boys don't go into each other's shelters at night. At full brightness, the stick lasted about 6 hours, but could still be identified for at least 2 hours from a distance of 100 meters. A good product