These collars inflict pain on your dog to get it to comply and are considered positive punishment. Science tells us that dogs can learn from this type of punishment, but there’s substantial risk of damaging your dog physically or emotionally. Before I became a trainer, I had a trainer recommend a prong collar to me for my German shepherd. In hindsight and with lots of training education I learned that using a prong collar was a huge mistake and resulted in my dog becoming aggressive towards other dogs. You see, dogs have what’s called superstitious learning. In my dog’s case, he saw another dog, got excited, pulled on leash, received a correction from me and then associated the pain in his neck with the other dogs. This illogical association can be made to children, fire hydrants, basically whatever your dog sees when it experiences the pain. Please save these devices as a last resort. If you feel you’ve already tried everything else first, consider hiring a certified trainer to make sure you’ve selected the right size collar, fitted it correctly and are using it as intended.