Keep threatening dogs away with the dog repeller.  Produces a discomforting but not harmful, high frequency sound, audible to dogs but no humans.  SImply point at the dog and press the button.   Dimensions: 3 3/4" x 2 3/16" x 7/8" Weight: 3.5 oz w/9-volt battery (not included) Frequency Range: 20,000Hz - 25,000Hz 135db Effective Range: Within 20 feet Also useful for training dogs!