Pethome Stop Barking Device Anti Bark Ultrasonic Dog Collar ON / OFF: The switch stop barking HIGH: High Audio Alert Settings LOW: Low Audio Alert Settings AUDIBLE: That changed this setting when opening remarks sound alarm occurs shrill beep to stimulate the dog to stop yelling into two HIGH and LOW alarm mode (large dogs can be set to HIGH, the puppy is set to LOW) ULTRASONIC: When this setting is turned into a ultrasonic control mode. Only then will your dog to stop barking at the induction run, people not sense. (This setting is absolutely no harm to the dog for the next night or a quiet environment)