Ultrasonic No Bark Collars are a wonderful way to teach your dog not to be barking all the time. There are few options when selecting Ultrasonic no bark collars, you can use a basic collar which responds with a sound when the dog barks from a sensor located in the collar. There are also collarless designs which hear the bark and then respond to it by sending an ultrasonic sound to correct the dog. The last option requires you actively training them because the sonic aspect is activated by you rather than a sensor doing the work.