Dog Bark Control & Pet Trainer: Our dog anti barking devices provide dog bark control and stop actions like fighting, digging, chewing furniture, eating unsafe foods, and other bad behavior. This device gently corrects bad dog behavior and is perfect for outdoor bark control. Persistence and patience are key, and remember to reward your furry friend when performing dog training and behavioral aids. Two Safe and Effective Frequency: This bark deterrent device can emit 25KHZ fixed frequency and 22KHZ-29KHZ variable frequency. Ultrasound is a high-frequency sound signal that is barely audible to the human ear, but it gets the dog's attention. No shock, no vibration, no noise, no touching the dog's skin, nor will it affect the dog's hearing, our device is 100% harmless to dogs and people. 50FT Control Range & Portable Size: Newly upgraded ultrasonic dog bark deterrent has a sleek appearance and small, lightweight design, dog bark deterrent comes with a wrist strap for you to carry around. The dog bark deterrent devices has a control range of 50 feet can be used outdoors and indoors with ease. Humanized ultrasonic dog training device completely liberates your dog from cruel shock collars.