Your pet's in safe hands. This training collar comes with 7 levels of sensitivity. Thus, you can set the level of signal you desire. The collar will react only to your dog's barking. If your dog barks for the first time, this prompts the device to produce a sound and/or a vibration. This trigger could go on and on, making stronger beats on the next level. After the seventh level, if your dog isn't still responding, the device will immediately stop and restart to prevent injury. If your dogs progress and react well you can decrease the level and set it to lower sound or vibration.