Some people advocate against using Dog Training Collars as these collars use shocks to train a stubborn dog. However, these collars are safe to use, and the shock managed by an approved shock collar is harmless. If you buy the caller from an authenticated source, you will get an excellent product. The impact of the shock is less likely to hurt a dog, but instead, show the dog that his trainer finds his stubbornness or aggressive behavior not acceptable. The use of the collar is not harming the dog. However, the trainer must learn how to administer and use the collar correctly so it can only serve as a learning tool and not something to scare your pets unnecessarily. You can learn about using these collars on your dog by talking to a pet trainer and get more information on these training collars.