The Gentle Spray Citronella Collar was developed using basic principles of dog learning and behavior plus the latest in technology. Heres how: When your dog barks, the collar sprays a burst of harmless citronella under his nose. While most people enjoy the fresh citrus fragrance of citronella, most dogs dont like it. They are also distracted by the "pssssst" sound of the collar as it sprays. When your dog barks, Citronella sprays in front of his nose! When your dog barks again, the scent and sound mysteriously reappear! Now your dog starts to get the idea that barking equals the sound and scent. A few more barks confirm the cause-and-effect connection. For most dogs, thats enough they will realize that when the Gentle Spray Citronella Collar is on, barking is not such a good idea. Best of all, the Gentle Spray Citronella Collar works even when youre not at home! Includes: Adjustable Nylon Web Collar Spray unit 2 batteries Citronella Spray (about 300 sprays)