Packing list: Dog whistle that can emit different frequencies to meet different command needs, such as recall, stop, etc. The dog recall whistle provides comprehensive training support for your dog to make it easier for you to deal with different scenarios. Silent technology with ultrasonic: Our high frequency silent dog whistle uses ultrasonic technology, the whistle signal emitted can only be heard by the dog, the human ear can not detect it, the dog whistle avoids noise interference to people, and can issue and execute commands to the dog more accurately. Increase the dog's responsiveness: With the Rütter dog whistle, the dog's responsiveness can be effectively improved. A training at Long-term training can give the dog a conditioned response, when it hears the dog whistle signal, it can execute your command, whether playing or working, it can improve the efficiency. Easy to carry: This set of ultrasonic dog whistle anti bark has a lanyard that allows you to hang it around your neck or hang it on a bag to avoid the trouble of easy loss. The small and portable design of the dog whistle allows you to take it anywhere to carry out dog training at any time.