Anti Barking Device: 2-in-1 ultrasonic Dog Trainer is a professional device for Dog Training and Dog Bark Control. The ultrasonic emitted by the bark control device can attract the attention of dogs and help prevent dogs from barking, digging, scratching,biting, climbing on furniture and other unwelcome behaviors. Two Safe and Effective Frequency: This bark control device can emit 25KHZ fixed frequency and 30KHZ variable frequency, which humans won't receive but it works for dogs. The dog whistle to stop barking has no shock, no vibration, no noise,no touchingthe dog's skin, nor will it affect the dog's hearing,so harmless to dogs. Suitable for small medium large dogs. Powerful and Easy To Use: dog barking control devices not only trains your dog, it also stops other dogs from approaching you while walking, jogging or biking. Just press the button and point the device at the dog while the dog is barking or approachingyou, and the dog will stop their bad behavior. Quadruple tap to switch between the two frequency modes. Longer Control Distance & Portable Size : The control range of bark deterrent is 16.4ft. The small dog barking deterrent along with a wrist strap is convenient for you to carry anywhere and easy to use Outdoor & Indoor.