We found a puppy, and decided to keep him. I had 3 cats and 2 other dogs at the time. We believe he brought fleas in because all of our pets seemed to be itching more than normal. Since we had so many animals, we could only afford flea collars for the cats. We bought HARTZ brand collars. 2 of the cats had no reactions to the collar, but my poor Biscuit experienced large sores that he could not quit scratching. They were all around his neck and face (which I would post pictures of, but I am in no shape to take pictures of my dead pet). I kept cleaning them and putting neosporin on them. I could not afford to take him to the vet for a while, but was planning to this Friday when I got paid. I was out today until about 9pm. When I got home, I fed the cats, but Biscuit did not come. I looked in his usual spot on the cabinets and saw his little paws hanging off as if he were sleeping. I called his name and touched his paws, but he was gone. He didn’t deserve this, and I feel so terrible that I purchased this product and put him through that misery. Rest in peace buddy, and I am so sorry I may have brought this on you. I will never be able to live this down.