Check the listing for details. Ultrasonic Pet Anti-Barking Device Dog Bark Control Stop Repeller Silencer Tool. Condition: New. Listed at 26.75 USD. Product features: 1. An ultrasonic anti-barking device can automatically detect dog barks 50 feet away. The barking control device automatically emits high sounds that only dogs can hear. After the dog stops barking, the ultrasonic barking control will automatically stop emitting an ultrasound. 2. Ultrasound is harmless to pets and completely inaudible to human ears, so the device can be used safely 3. Can be hung on a tree, indoor, or outdoor wall, or fence to prevent dog barking (within range). When the luxurious outdoor ultrasonic barking alarm clock detects excessive barking, the microphone will respond to the barking and activate components. 4. Suitable for dogs from 6 months to 8 years old. Packing list: 1 x Anti-bark device 1 x USB cable 1 x Instruction book