Bests & Worsts Reviews from Amazon

We purchased the first collar from our Vetinarian, and the results were an amazing transformation for our dog . Very positive at this point. The product is supposed to last for one month, which it basically did. We then purchased the second collar from Amazon, and almost immediately we saw something was not right with our dog. She seemed very lethargic . 3 hours later she was trembling. We removed the collar and within 5 minutes she was her old energetic self again. We are at a loss as to why the first collar was such a positive experience and the second collar was such a negative experience. There will not be a third. We returned the collar to Amazon.