SENTRY Calming Collars use patented GOOD Behavior pheromone technology. Using a pheromone that mimics the one mother cats produce to calm their kittens, the collars are clinically proven to reduce or eliminate stress-related behavior such as inappropriate marking, destructive behavior, clawing and anti-social behavior. Collars help alleviate problem behaviors triggered by travel, thunderstorms, fireworks and new social situations. This collar continues to release calming pheromones to your cat for 30 days. It can be used for cats of all ages and breeds without long-term side effects. This economy 3-pack is perfect for multi-cat households.