Keep your cat feeling right at home with the Feliway MultiCat Diffuser Refill. When a cat has kittens, she releases natural, calming pheromones as her kittens start to nurse. This refill is designed to work with the Feliway MultiCat Diffuser, and its a synthetic copy of that pheromone. By mimicking this bonding pheromone, Feliway creates a state of calmness and comfort to alleviate tension and conflict between cats. As a result, Feliway can be used to help reduce tension and conflict in multi-cat households.