Helps reduce fear of loud noises, bad behavior and barking. Features patented GOOD Behavior pheromone technology. Uses a pheromone that mimics the one mother dog produces to calm her puppies. Clinically proven to reduce or eliminate stress-related behavior such as inappropriate marking, excessive barking and chewing. Helps alleviate problem behaviors triggered by travel, thunderstorms, fireworks, being left alone and new social situations. Safe and effective for dogs of all ages and breeds without long-term side effects. Fits up to 23" neck.