Some hand-held transmitters broadcast irritating or high-pitched sounds when you push the button. We don't usually recommend this type, as the drawback is, of course, that you must be present to administer the correction.
Other sound transmitters are activated by the sound of a dog barking. These are particularly useful in situations when you want to stop a neighbor's dog from barking.
Bark Collars are the most effective bark control and come in three types:
Sound-emitting collars shriek when the dog barks. It irritates and distracts the dog.
Spray collars spritz a burst of citrus spray directly in front of his face. It's surprising so it distracts him. It is also bitter in the sinuses, so he doesn't like it.
Static correction Bark Collars give your dog a static shock when he barks. Everyone hates to use these collars, but, in actuality, they are safe AND humane. The corrections is much like the shock you get from touching a metal door knob when you have charged your body by shuffling on the carpet. Unpleasant but harmless.
Given this surprising little zap, the dog quickly learns that his own behavior causes the correction, and he ceases to bark. You will be surprised at how quickly he learns.
If you have more than one dog, it is important that you purchase a collar that has technology to correct only the dog that is barking. Best collars use a collar-mounted-sensor that "feels" the vibration of the vocal chords AND a small receiver that "hears" the sound of the yap. That way, one dog's barking will not set off another dog's collar.