The ultrasonic sound is 100% harmlessCollar is an advanced behaviour modification device designed to help train your dog to stop excessive barking. This Dog Collar eliminates interruption from another dog. You can truly enjoy the outdoors with your pet， and eliminate nuisance barking. The Bark Stop Collar is an advanced behaviour modification device designed to help train your dog to stop excessive barking.The Dog Training Collar is activated through the bark vibration of the dog wearing collar. This Dog Bark Collar eliminates interruption from another dog.You can now truly enjoy the outdoors with your pet， and eliminate nuisance barking.The Dog Collar straps are elasticated with an buckle.Features:Color: WhiteWeight: 40gAdjustable stretch collar to fit different sizes:(abt.) Longest: 11.5"， Shortest: 7"， Width: 0.5"Powered by 2 AG10 cell batteries (included)Simply adjust collar to appropriate size for your dog's neck and put it up. Use On/Off button to turn it on/offHigh Button: Setting the collar on this setting will set the sensitivity of the unit at higher settings， which means even soft bark will cause the unit to activateLow Button: Setting the collar on 'Low' setting will only activate the unit when more aggressive bark occursAudible: Audible will allow everyone to hear the unit activate. This setting is recommended for testingUltrasonic: This is the recommended settings for daily use. This unit will emit ultra-sound only your dogs to hear. Your dog will feel uncomfortable and stop barkingPackage included:1x Bark stop collar1x User manual2x AG10 batteries