Ultrasonic dog trainer detects and deters nuisance barking.
Note: Not recommended for indoor use: if you're wanting a product to use indoors, you'll need to use a collar. This is because the ultrasound noise emitted by these devices will not pass effectively throughout the enclosed areas of a house. A collar will of course stay with the dog and will therefore be effective throughout the house.
As with all products involving animal behaviour, results vary from one dog to another: whilst many dogs are trained quickly, some need more patience and perseverence and in rare cases the results may be less than totally effective.