The Goldman's Small Dog-Friendly No-Bark Collar is a humane no-bark training collar that uses sound or vibration to distract your dog when barking to help curb destructive behavior. This safe collar has 2 modes: sound and vibration. Barking will activate the collar. Features - 2 lithium batteries (plus 2 replacements!), clip-on safety light, and LED light mode indicator. Fits neck sizes up to 13"-22". This dog training tool clips onto your dog like a regular collar.