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The problem with commercially available ultrasonic dog barking deterrents are they lack sufficient intensity and range to be effective against a neighbors barking dog. Although the dog next door might be able to hear the device, it would be the equivelent to a human hearing a wind-chime. The dog might respond at first, but merely out of curiosity then simply ignore the sound in some cases even become accustomed to it and enjoy it. Commercially available ultrasonic dog barking deterrent = pleasant wind-chime to the dog next door.