1.Effective Potty Training: Do you want your puppy to communicate in a friendly way instead of barking, and scratching? This dog doorbell is the perfect choice. Dog can communicate his needs to go outside by ringing bell. Hanging dog door bell make training so easy, no more accidents in the house! A must have pet supplies at home 2.Easy to Train: Just follow our easy 3 step training guide. Teach your doggy to ring the bell as a signal for when they want to outside. After doing this several times, you will have a dog that communicate with you. In addition, our dog doorbells come with instructions on how to train the dog to use, It will help you effective and easy train your pets 3.Adjustable Length: adjustable dog door bell grows with your dog from puppy to senior. The length of dog bells for door knob can be ly adjusted to fit any size dog or the height of the door by using round spring clip snap. The metal clasp design allows you to hang this door bell for dog on any type of the door knob handle, even on sliding glass door handles 4.High-Quality Bells: 6 vintage bells are made of metal, bronze-plated outside, durable and solid, anti-deformation and rust-resistant. Training bells for puppies are suitable for outdoor or indoor use. The bells are loud and clear and can be heard throughout the house, but not to loud to being annoying