This is going to seem strange. I ordered this pen light on accident, I thought it was a space pen with a light on the end but it ended up being a blue spot light pen, seemingly useless even as a pocket flashlight because it was blue. However one night I got up to pee in the middle of the night and grabbed the blue penlight, I keep it next to the bed because the light is mild on the eyes and good for low light navigation. I decided to check on the tank.... well come to find out the blue light from this flashlight is amazing on corals, in the middle of the night any corals that were open the colors were brought it almost as well as my kessil leds and some corals even opened up more to accept the light! I was so surprised. If anyone is looking for a good nighttime viewing light this is the one to get. Ill post a link tomorrow to the light, but fisher space pen light. I'm on my phone now