Bark Control and Dog Training - The ultrasonic anti bark device for dogs is a great device for dog training and dog bark control. The tuned ultrasonic frequency (24KHZ) has a certain effect on dogs and helps you to correct their behavior. Safe and Effective - The average human hearing frequency range is 20Hz-20kHz and the dog can hear a wider range of 15 Hz to 120 kHz. The ultrasonic bark control emits 24KHZ ultrasonic sound, so the sound does not affect humans, but can attract dogs' attention. For indoor and outdoor - This anti-bark device has an effective control range of 5 meters. You can use it to train your own dog or you can transport it to hunt hostile dogs you encounter on the road. Perfect for indoor and outdoor use. Suitable for Dogs of All Sizes - The Anti-Bark Device is an innovative solution for dog barking and the correction of unwanted behavior. The ultrasonic dog trainer is safe and effective for all types and sizes of dogs (5-120 lbs). Suitable for dogs from 6 months to 8 years old. Easy to use - When you press and hold the button of the ultrasonic bark control devices, it emits an ultrasonic sound that can only be heard by others. dogs, release the button to stop. No more complex operation is necessary. Scope of delivery: 1 set (host, manual, USB charging cable, lanyard) Color: Black Note: The data is all manual measurement, please allow 1 - 3cm error, due to the difference in light and display, there will be some color difference, depending on the physical object received Delivery Quantity: (according to the main picture)