Introducing a new feline family member to the household is easy with the Comfort Zone Feliway Multicat diffuser refill. Feliway mimics comforting cat pheromones that help multiple cats feel calmer when they share an environment. The veterinarian-recommended calming pheromones can reduce tension and fighting among household cats. This formula is unscented, drug free, and has been clinically proven to make cats more comfortable. One diffuser refill can cover up to 650 square feet of living space.