Your pet is in safe hands. This training collar features seven levels of sensitivity. You can set the signal level you want. The collar will only react to your dog's bark. 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 for a long time, producing harder beats to the next level. After the seventh level, if your dog is still not responding, the device will immediately stop and restart to avoid injury. If your dogs are progressing and responding well, you can lower the level and set it to a lower sound or vibration.