Use the Feliway Classic 30-Day Refill to easily refill your diffuser and continue providing room-wide pheromone therapy. Refill cartridge contains clinically proven synthetic calming feline facial pheromones that help control unwanted behaviors including urine spraying, inappropriate scratching, and hiding. Used in the Feliway Classic plug-in diffuser, the Feliway 30-Day Refill helps curb your cat's stress response in situations such as moving to a new home, rearranging furniture, visiting the veterinarian, hospitalization, travel, boarding, meeting new animals, and meeting new visitors. The synthetic F3 Feline Facial Pheromone formula contained in the convenient Feliway 30-Day Refill cartridge communicates a reassuring message to your cat, which helps curb or eliminate unwanted behaviors.