Feature: 1. Ultrasonic anti-bark device can automatically detect dog barking from 50 feet away. The barking control device will automatically make a high sound that only dogs can hear. After the dog stops barking, the ultrasonic barking control will automatically stop emitting ultrasound. 2. Ultrasound is harmless to pets and is completely inaudible to human ears, so the device can be used safely 3. It can be hung on the tree, indoor, outdoor wall or fence to prevent the dog from barking (within the range). When an excessive bark is detected, the microphone will respond to the bark and activate the component. 4. Suitable for dogs from 6 months to 8 years old. Specification: Material: ABS Color: Black Battery capacity: 1500mah Size: 11*8.5*4.85cm/4.33*3.35*1.91in Package included: 1 X Bark Stopper