Bought it November 2016. Arrived promptly. Didn't open till January 2017. I rarely walk dog art night. So though this i's August, I used it only about a dozen time. One collar is going strong. The other collar, the one with the short charge even from the beginning, no longer works. Will email seller.
I gave it 4 star because it lights up great. My black dog is visible. It's easier to put on than the reflective vests and much better visibility.

Update: well I gave it the benefit of the doubt. Bought another one so I can see the dogs at night during camping. 4 uses and battery is dead.

Bought the Green Collar and the pink LED Necklace Collar... Both are very bright. Dog wore the green collar two nights in a row over 8 hours each before it needed recharging. Hopefully we will no longer trip over our very large and very black GS, hurting ourselves and the dog. I need a bracelet size to put over his tail so I'll have a better idea where his body begins and ends (lol). I can tell where his head is now, but I can't tell in which direction his lying; i.e. where his butt is. Our house is small and the only place the dog has to lie down other than his bed is where people have to walk and he is impossible to see in the dark even when there's a little light. I don't know how long these collars have been around, but their time has come, such a wonderful idea.

We have two dogs and occasionally dog-sit for a third, so I have three of these now. Purchased the yellow one first, last summer, it's not a bright yellow more of an amber but it works. We have a big yard and the porch lights don't reach the far corners, so this way we can keep track of our pup at night. The green one was purchased second, it's a beautiful color, prettier and brighter than the yellow one. Just purchased the blue one last week and it's just as nice as the green one. Not quite as bright but a very pretty color. Thumbs (and paws) up all around.

This is a very bright and good quality led collar. I got the medium for my dog who usually uses 16" collar and it fits. He is a 45 lb slender built dog and the 1" collar might be a bit thick for him as we are used to a thinner width. But that's just preference. It is a sturdy design and probably less heavy than others like it I have seen at stores. Only thing that would make it better for me would be a thinner width maybe 3/4 inch and if it were water resistant that would be nice. He rolled in poop and got it all over the collar. I used a very wet rag to scrub it down and was careful by the button and it still works.

Editing my review: Since my original review my dog has slipped out of the collar again since it doesn't stay size adjusted and then chewed through the collar so now it's basically useless to me. It's a shame too because I really liked the collar. I tried buying the next size down thinking maybe this one just needed to be adjusted too much but the next size down is too small so now I'm stuck with 2 useless collars.
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I love the brightness of this collar and it lasted a long time before I just recently had to charge it for the first time. My only complaint so far is that our dog slipped out of it on her walk one day. She pulls on her collar during walks and if you have to adjust the size to shorten it up it doesn't hold the size very well in that situation allowing the dog to get it's head out. We just went back to using her old collar to hold her leash for walks but keep this one on her for it's light. Overall, it's still a great collar. I just wish it could be adjusted and stay put better for dogs that pull hard on leash.