FEATURES [Upgraded Dog Training and Behavioural Aids]: Using the latest ultrasonic technology, the anti-barking device will automatically emit a high pitched tone that can only be heard by the dog. It automatically senses the dog's voice and once the dog stops barking, the ultrasonic bark controller will automatically stop emitting ultrasonic waves. [Safe for Dogs and Humans]: Dog Bark Control Device has no electric shock, no irritating odour, no beeping, no harm to pets, the anti-barking device will automatically emit ultrasonic waves to prevent your dog from barking, perfect for going out when you are away from your dog. Dogs stay quiet,create a quiet environment for your family and neighbours. [STOP DOG BARKING INDOORS AND OUTDOORS]: Tested with anti-barking devices, it completely frees your hands compared to traditional dog trainers. Easy to train your dog's behaviour with the turn of a knob. Great for stopping neighbours and homeless dogs from barking outdoors. Product Name: Ultrasonic Bark Stopper Product Material: Plastic Product size: as shown Colour: Black Packing List (available upon purchase of one product): Stop Barker x1 Please understand: 1.Due to the long shipping time, the item may be damaged during shipping. If the item is damaged, please leave us a message through the official website immediately and then post a comment, I will solve the problem for you. 2. Due to manual measurement, the size may have 1-3cm error. 3. Colour may vary by monitor.