This a non-shock collar that uses vibration/tone correction. The Pet Pager was designed to help pet owners silently call their dog from a distance. It can also be used to dissuade or interrupt negative behavior. It works similarly to a personal pager. The pet owner uses a hand held transmitter to send a signal to their pet. The pet wears a receiver collar that vibrates when it receives the signal. With a little training, the pet quickly learns to come to the owner when it receives the "page". The Pet Pager is a great training tool and an indispensable aid to owners of deaf or hearing impaired dogs. PetSafe PVPP-300 Pet Pager Vibration Control Trainer Features: Ideal for deaf or easily-distracted dogs. Harmless vibration "pages" your pet! Range up to 100 yards. Long battery life. Adjustable collar, from 6" to 28". Receiver uses one 6 volt Alkaline battery included. Transmitter uses one 9 volt Alkaline battery included.