Comfort Zone Multi-Cat Diffuser Refills are designed to help reduce common signs of stress in multi-cat homes and households with multiple cats, supporting calmer interactions, cat stress relief, stress reduction, and improved cat behavioral aid. These pet care essentials are a must-have for cat owners and pair with all Comfort Zone cat calming pheromone diffusers - ideal for indoor cats and their everyday stressors like routine changes, new environments, and visitors. A cat plug in pheromone diffuser must be used with this product.Each refill delivers 24/7 calming for up to 30 days for everyday use indoors, helping maintain a consistent calming environment for indoor cats in multi-cat homes. The fragrance-free, drug-free pheromone formula mimics a cat's natural calming pheromones, which cats instinctively recognize as a signal that an area is safe, familiar, and secure. These refills help reduce behaviors including urine marking, scratching, swatting, biting, fighting, growling, hissing, and blocking. Most cats begin to show improved behavior within as little as one week, with continued stress reduction benefits through regular use.Each refill is designed to cover one room in an open area, and for best results avoid placing under shelves, behind furniture, or near vents or windows. Easy to use and mess-free, Comfort Zone Multi-Cat Diffuser Refills are expert recommended and tested to meet electrical safety standards, offering peace of mind for cat owners in households with multiple cats. Replace refills monthly for continuous calming support and a more comfortable, stress-free home.