Anti Barking Device Ultrasonic Dog Trainer Bark Repellent For Dogs Ear: 12x8 cm/4.7x3 inches Designed like an alarm clock, it can be hung on a tree, anywhere in your home or yard, or placed on a table or elsewhere When the external ultrasonic barking alarm clock detects excessive barking, the microphone will sense barking and activate components that will emit a safe high-pitched ultrasonic sound to make sure it will be heard and stimulated by dogs that may stop barking,Because ultrasound can make the dog feel uncomfortable Designed do outdoor use, outdoor ultrasonic cork stoppers are durable and waterproof There are 3 sensitivity levels (effective range is 4,5m, 9m do 15,24m) and test range 9V battery required (set not included) The outdoor ultrasonic bark has a power indicator that can be turned off when you go out to protect the battery The package includes: 1 piece anti-barking device