I've got a black, 4-yr-old Great Dane and come hell or high water, he needs his walk. Late hours at work means that we often don't get our 2-hr-walks started until evening. In the deep woods under a new moon, it's pitch-black. We can't see where we're going nor can others see us. A light was, and still is, a must. I tried, and quickly dispensed with, traditional LED flashlights. A flashlight is extra work for your hand. In the woods, sometimes you have to clear vines from a trail at night, occasionally you might need to wrestle a gator. Can you do that with a flashlight in one hand? No, and again NO! Being a thinker, a light bulb went off in my head, actually above it because it was a headlamp. A headlamp is better than a flashlight in the fact it frees up your hand, but worse because you'll blind whomever or whatever you're looking at. There's nothing more obnoxious than a hiker with a headlamp or bikelamp blinding you the entire time they're riding your direction. There's one other negative I associate with a headlamp and a flashlight. While they might help me observe my surroundings, I can't easily spot my dog, nor can others (he's black). I tried a blinking LED and while that made it easy to spot the dog, it was hell on the eyes. The designers of that object had a setting that allowed the user to change the collar from blinking to a slow color changing and it was while using that completely different collar that one night, while walking down the trail, I noticed I could see where I was walking solely from my dog's LED collar. It was then I asked the question, "Why hasn't someone invented a dog collar flashlight?" I went online and found a link for a company that made just such an object and then looked up the object on Amazon.com and decided to buy it. From day one, I have been very pleased. The light is bright and diffuse. You can change the angle of the light by swiveling the plastic piece attached to the light and collar and it stays in place. This collar is great because if my dog is wearing it, I don't need a light myself. It's great because it lights up the ground and doesn't blind my dog or other folks hiking past. By using rechargeable batteries, I have used this light over and over and over without any problems. I am getting a Giant Schnauzer puppy in a week and we'll be getting another PupLight collar. I have been satisfied with my purchase. Although I can't say for sure, I believe my dog likes it too because whenever I grab the collar, he wags his tail. That might have more to do with knowing that we're going into the forest, but the collar is comfortable for him and although dogs can see better than humans in the dark, on dark nights when the moon's not out, even a dog will bump into things. With the PupLight, the task of walking, observing, and in the instances where I'm near areas of traffic, being visible to cars has become easy. I know for sure they'll see us crossing the street. As a result I highly recommend this collar and I am basing my review from the long life, consistent brightness, and good design. It's a great deal.