Sound-Activated Collar for Controlled Barking Hagen Pro No Bark Collar is made to distract dogs from barking. It works on stubborn dogs and corrects excessive barking with sound and vibration modes. It also features high and low stimulation levels to customize settings for your dog. This lightweight collar is powered by 3 L44 1.5 V batteries.Hagen Pro No Bark CollarCollar with vibration and sound modesTwo modes of correctionUseful for deaf dogsSafe and humaneShower proofHagen Pro No Bark Collar works effectively but without being aggressive on your canine friend. It doesn't release any kind of shock.