Dog Bark Control and Dog Training - Our ultrasonic anti barking devices provide a safe and effective solution for dog training and bark control. The anti bark device can effectively train your dogs to stop unwanted behaviors such as barking, digging, eating unsafe food, fighting, etc. Work Principles - The average human hearing frequency range is 20HZ - 20KHZ, and the dog can hear a range from 15HZ to 120KHZ. ultrasonic bark control emits ultrasonic sound at 25KHZ, so the sound doesn't affect humans, but can take dogs' attention. 16ft Control Range for Indoor and Outdoor - This ultrasonic bark deterrent has 16ft effective control range, which is longer than the normal range 6ft. And its portable design makes it suitable to be used indoor or outdoor. You can use it to train your own dog, or you can carry it around to drive away unfriendly dogs you encounter on the road. Easy to Use - When you press & hold the button of the ultrasonic barking control devices, it will emit an ultrasonic sound that can only be heard by dogs,release the button to stop. The LED indicator lights up green when the device is working and emitting ultrasonic sound. Press and hold the button for over 6 seconds, the barking control devices will shut off. User's Guidance - Not recommended on tiny dog (less than 4.5lb). The ultrasonic anti barking device doesn't effective in dogs with hearing problems or older dogs. Training is required to achieve highly effective and long-lasting use. 1. This device is not intended to provide protection against aggressive dogs, can not be used to defend against fierce wild dogs 2.Different dog breeds may react to the ultrasonic sound differently. For optimal results,please use the ptoduct as a training process. 3.To avoid desensitizing your dog,only turn on device during periods of inwanted barking. 4.The device should be taken facing the dog and whthin range the range of the dog(max16ft). 5.Please charge the device before every usage. The device can contiguously can work for 8 H after fully . During charging ,the red light on means charging,blue light on meas fully . colour:Black Material:ABS size:37 x 25 x 100mm Package Contents: 1 x Ultrasonic dog Training Device 1 x English manual 1 x USB charging cable Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.