Uses pheromone technology that's proven to modify behaviors caused by stress and fear, such as inappropriate marking, chewing, excessive barking, jumping, and destruction. Releases a pheromone that mimics the one mother dogs produce to calm and soothe puppies, making dogs feel safe and secure. Helps alleviate problem behaviors caused by stressful situations such as travel, thunderstorms, new pets in the home, new visitors, car rides, and vet visits. Releases pheromones for 30 days with a pleasant, soothing lavender chamomile fragrance. Adjusts to fit necks up to 23 inches. Can be used for dogs of all ages and breeds with no long-term side effects. Calming Collars use patented Good Behavior pheromone technology. Using a pheromone that mimics the one mother dogs produce to calm their puppies, the collars are clinically proven to reduce or eliminate stress-related behavior such as inappropriate marking, excessive barking and chewing. Collars help alleviate problem behaviors triggered by travel, thunderstorms, fireworks, being left alone and new social situations. This collar continues to release calming pheromones for your dog for 30 days. It can be used for dogs of all ages and breeds without long-term side effects. Fits Up to 23-inch neck.