Fashioned after the Ultra-e series, this ultra small size bark collar fits the smallest of dogs to the largest of breeds (6.5" to 24" adjustable collar neck sizes). Collar unit measures just 1 1 or 4" x 1" x 1 7 or 8" and weighs approximately 2 oz. This collar uses a 6-volt lithium or alkaline replaceable battery. High quality sensor picks up vocal cord vibrations when the dog is barking and triggers the correction. Eight levels of intensity, adjustable directly on the collar. Automatic three-second safety delay between stimulations gives your dog added protection. Waterproof.