Pleasantly surprised to receive my collars and discovered theyre not cheap or flimsy feeling. They are strong and appear well made. They light up really bright, making your dog visible for quite some distance. The large is quite big; suitable for a German Shepherd, lab, or other big breed. The medium size collar is also kind of on the big side. At first it was much too big for my 25lb Benji-type dog, but i was able to adjust it to fit acceptably. It is a bit bulky on smaller dogs though, and a little tricky to adjust. But still useful. I would recommend to the seller that they try to make the smaller collars a little more flexible and not as bulky for smaller dogs (under, let's say, 35lbs or so). On bigger dogs, no problem!By the way, this company also sells glow leashes. I have one of those and it is also well made and lights up really bright. These are great for any size dog.Another thing, you can always use this collar as a sort of secondary collar. I think that is what i will do with my dog since this collar is rather bulky on her. I have her standard, functional but not as fun collar on most of the time, and then i will put the glow collar on when i take her for walks or to the dog park!I would still recommend these collars regardless of the size of your dog, as they should help keep you and your dog safe when walking, plus they are just lots of fun to just to run around the backyard with them at night. Definite attention getters!I’ve had the cheaper non rechargeable collars and they work great too. I wanted to try out the rechargeable ones to see how long they last. It’s only been about 2 months but so far mine works great. I’ve recharged it more than its needed. I keep it and the charging cord hanging from my rearview mirror in my truck and put the collar on my dog when we go to the city dog park late at night when I’m not working 3rd shift. It’s a very visible red light that has 2 flashing modes, an on mode and off. It hasn’t been submerged in water so I don’t know how well that works. Worth the money and everything appears to be made of good quality materials.I purchased two of these, one pink and one blue. The pink one lights up along its entire length with good visibility - even on a longer haired dog. The blue one only has a strip of lighted area that is about 7 inches long. I thought it would light up along its entire length like the pink one does. It rotates around my dog's neck so that the lit area is not always in the best area for visibility. (I won't make it tighter and choke him) Both collars seem well enough made and durable in appearance. They came in the exact same packaging but are different products. The pictures on the listing are misleading. I noticed that they give an option of 'blue' and 'royal blue' but there isn't any explanation for the difference. The picture of a 'blue' collar looks like it lights up around it's entire circumference. I will be returning this.Update: The seller initiated and refunded the full amount of the cost of the blue collar, which I appreciate. I have upgraded my rating because of excellent customer service.UPDATE: Great customer service, corrected the issue and are working on improving their products.We bought 2 for each of our dogs. These are heavy duty but they don't even hold a charge for our 30 minute walks. Only used 2x. Will be Returning both.Love it but really wanted a bold PINK lite an not so much Red lite coming from a Pink collar. But other than that great item and great deal.As every described the collar was stiff at shipment, but we correct this by rubber banding the collar into a ball when not in use and it's fine now after a few weeks.Walking at night. Finn is black so this helps me see her.One day if ownership, good quality, really wanted pink, it's red. Customer service was amazing they reached out and made things right. Don't mind the red, but didn't expect it. Works great and looks good would recommend.