Ultrasonic Dog Repeller 16.4ft Range Frequency Adjustable Handheld Dog Barking Control Device with Lanyard Item Type: Ultrasonic Dog Repeller Material: ABS Effective Distance: Approx. 5m / 16.4ft Battery Type: 4 x AAA Batteries (not included) Suitable for animals such as dogs, cats and snakes. Problems with the use of product features: The ultrasonic frequency emitted by the ultrasonic dog repeller is 25-30KHz Different pets will have different reactions to the waves in this frequency band. Some dogs will feel uncomfortable and stop barking immediately. Some dogs feel comfortable hearing, will slowly quiet down and stop barking. Some dogs are not sensitive to ultrasonic, and they get used to it after listening to them. Not useful for pets either. In general the following ultrasonic products are not effective for pets. 1. A trained dog 2. Dogs who are not sensitive to ultrasonic 3. Dogs with ear injuries or hearing impairments 4. Ultrasonic hears too many dogs that have developed antibodies to ultrasonic