DO NOT USE THIS COLLAR
599024
My cat has been acting bizarre for two days, extremely overly playful, and driving our other cat nuts by constantly nipping at him.  This morning he became violently ill.  He was vomiting and then a cry after.  He now has the dry heaves.  I thank God I read the review about this collar killing other cats.  He has had the collar on for two weeks.  I have cut if off of him and cut off my other cat, which I just put the collar on yesterday, for fear it will make him sick and possibly killing him.  I previously posted this review  and forgot to mention his bizarre behavior, which I now realize was connected to this dangerous collar.

DO NOT USE THIS COLLAR.

DO NOT WASTE YOU HARD EARNED MONEY ON A PRODUCT THAT COULD KILL YOU BELOVED CAT.
1683093
Really bad experience. Got a defective product and could not take it off my dogs collar. Had to litrally cut it out. My puppy went through a traumatic  experience as she did not deal well with a scissor near her neck.

Save your money and time and stay away from this product.
153027
The collar started to fray very quickly and looks terrible. We have had it for less than a month and I already need to replace it.
214515
This product caused my bulldogs neck to break out in huge welts that turned into a bacterial infection. We had to go to the vet and get antibiotics. I will not buy this again.
162548
This collar is junk.  It will not turn on and is complex. It's not even worth the money if it did work. Sending it back.
4831915
This collar doesn't work at all. It would start going off if my dog was playing enthusiastically or when he jumped off the couch. When he was actually barking non stop it did nothing. I've adjusted the sensitivity and it makes no difference. Just now while he was lying down it started constantly beeping for no reason. I had to remove the battery to make it stop. Of course I am just outside the one month return policy.
736516
This collar is not effective against ticks - there were ticks on my dog. Even around his neck area where the collar is .
Want a refund.
1049627
DO NOT GET THIS COLLAR. After not even a month having it and only using the shock a couple of times the battery leaked all over my dogs neck. It left burns and a hole filled with puss. His neck has no hair now and is burned. We only put the shock up to 15. It goes up 99. It was not us shocking him, but the collar exploding. DO NOT BUY.
678770
The collar is very bulky and needs to be refilled constantly. It also does not function consistently. I do not recommend. I would not purchase this item again.
4479549
For your cats safety...BEWARE! I have bought a few of these collars. I like to make sure my cats have a collar with a name tag on them at all times, just in case they get out or lost. My youngest cat she still wears hers and its been months with no problem. My older cat kept scratching her neck. I guess she was not used to the collar. I noticed that in time her collar would get tighter and tighter around her neck. I kept thinking I bought the wrong size or it was defective, so I ordered a new one and replaced it. The price was cheap and reasonable. But the last collar I ordered just a month ago became so tight, so quickly that I was horrified. I tried to get it off but It was so tight around her neck that I had trouble. Now reading the other reviews, Im here to validate the negative ones. THE MORE THE CAT SCRATCHES THE COLLAR.......THE MORE WORN OUT AND TIGHTER IT WILL GET.............BECOMING A CHOKE HAZARD!!!!!!!!!!!!!
4729745
This collar is horrible!!! It stopped working after on use. Amazon sent me a replacement and THAT one broke after only one use. They just stop spraying. I made sure the battery works and the collar is full of spray. DON'T BUY THIS COLLAR! I will be requesting my money back. I wouldn't give it even 1 star.
396477
I got caught with my dog out in a heavy rain with this LED collar on. Needless to say my dog & her collar were soaked. The lights on the collar never worked again after it got wet. So I won't recommend this collar to anyone.
3742645
Updated

Fence works well, collar is horrible.  First collar randomly shocked my dog.  I made the seller aware and they shipped me a replace within two days.  I have spent the past two weeks watching my dog randomly get shocked in the middle of the yard, when she happens to run at all in the back yard it beeps and shocks her.  My daughter will not let her wear the collar when they are playing in the yard cause it randomly shocks her, no where near the fence.  When my dog wants to go outside, I put the collar on, she chooses not to go outside because she is afraid of the collar.  Poor quality, and no way to reach seller to help
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Purchased cause of the price, works.  The collar was broken when we got it.  Had two plastic washers holding it on and they were broken when we put the collar on our dog.  The first time she put it on it fell on the ground.  Used a knife made two smaller holes screwed the collar on and its stayed since.  Flags are basically straws with a flag on the top, need soft soil to put in.  Had to buy extra wire as the 500ft wasn't enough.  Make sure to measure your yard to make sure you have enough.

Training was easy, 3 day training no shock and 4 day dog tempted the fence and learned quickly, hasn't ventured near the fence since.
826534
We bought two collars.  At first, both worked well and then over time, one of the collars started discharging shocks at random.  The dog would be walking or just standing there and get shocked.  Of course, I took the collar off and put it on my counter to try and figure out what to do.  It's pretty expensive to stop working after a few months.  Well, I reached across the counter to grab something and my wrist brushed the collar which gave me a nasty shock.  It was very painful (went right up my arm) and left a burn on the skin (I included a picture taken 2 days later where you can still see the mark).  Now I'm afraid to use the other collar as well.  I wouldn't recommend this product.  It is unsafe.
2021521
No sooner than I put it on my cat, it was off.  I tried multiple times and each and every time, it opened up.  I tried making it tighter, that didn't work.  I tried loosening it, that didn't work.  I would NOT recommend this collar.
3280569
I have had to repurchase the collar alone twice now. The original kit lasted maybe a couple a couple of years then stopped working. Purchased a new one In January 2017 off of Amazon and by July I again had a non-working collar. The only reason I re-purchased it was because I already have the barriers (3 total) and didn't want to have to replace those as well. I tried replacing the batteries in the collars and got nothing. When the new collar arrived I tested it and yes, the barriers are working and the collar was beeping when I moved the new collar towards them telling me it was definitely a collar issue. Save you money. If an 8 lb dog wearing it 8-10 hours at a time breaks the collar unit, then it is obviously a cheaply made product.
2938533
Collar was too small.  It may have started out at 16", but when they sewed on the clasps, it ended up smaller than that.  Really was about 13" collar.  Also had a number of sharp threads pointing out on the inside of the collar.  It would have hurt the dogs neck.  I did not use it.