【Effective Ultrasonic for Most Dogs】The dog bark control box is suitable for most breeds and sizes, but not suitable for deaf or hard of hearing dogs. Some dogs may be afraid or dislike the sound of the ultrasonic wave, so they may not stop barking at first. Please allow up to 2 weeks for training. Safe and Effective Ultrasonic Bark Control: The sound is harmless to pets. If the dog is hard of hearing or aggressive, the bark control may not have the desired effect. It is not recommended to use an ultrasonic dog device against two or more dogs barking at the same time. 【Easy to Install & Waterproof Anti-Bark Device】The anti-bark device is designed to be easily hung or mounted on a tree, wall, or fence post to prevent your or your neighbor's dog from barking. Make sure the ultrasonic bark control system is facing the dog in an open area. Product Description: The product is designed to look like an alarm clock. The Deluxe Outdoor Ultrasonic Bark Deterrent can be hung on a tree, anywhere