FeaturesSafe and efficient dog training & behavior aids:dog barking control devices emits an ultrasound of 20~25 KHZ, which exceeds the range of human hearing but can easily lead to the dog's attention without hurting your dog like a dog whistle, safe to correct unwanted behavior and stop dog barking or prevent eating unsafe food, effective pet corrector for dogs of all types and sizes of age 6 months to 8 years oldSonar heads up to 10m/32ft range effect:this anti-barking device with dual heads has higher power and is more effective than the single head on the market, this electronic dog whistle equips with an 800mah rechargeable battery, provides a full charge in 1 to 2 hours for about 30 days of regular useTwo modes with a flashlight ultrasonic dog whistle to stop barking, Deterrent mode:emit a higher intensity ultrasonic sound while the flashlight flashes to drive the fierce dog away, Training mode: emit a lower intensity ultrasonic sound to assist in daily dog training such as stop excessive barking, fighting, biting, and correct other unwanted behaviors, the flashlight also has a long-bright mode for walking your dog at nightSlim design with anti-mistake lock key:this dog barking deterrent device is slimmer that makes it is better to fit even in a smaller hand, the independent and clear keys make it easy to use, the anti-mistake lock key will avoid false triggers, and also come with an adjustable wrist strap for use outdoorThe button pressing with vibration effect:when pressing the button of this ultrasonic dog bark deterrent device, it will also have a vibration effect, which will bring you a better experience, and the button light indicator will be red in low power