Are your cats fighting, or is there tension between cats in your household? FELIWAY MultiCat is vet recommended, drug free, and shown reduce tension and fighting among cats in the home. Signs of tension could include chasing, blocking, staring, fighting, or hissing among cats. By mimicking the natural feline appeasing messages (pheromones), FELIWAY MultiCat sends “harmony messages” to help your cats get along more effectively, and avoid tension, conflict and fighting in the home. Most cat owners see a 70% reduction in conflict in 3 weeks. This FELIWAY MultiCat Refill Set includes three refill vials (diffuser head not included). You should plug your diffuser in the room(s) where your cat spends the most time, and make sure it isn't covered by curtains, or behind furniture. Each diffuser covers up to 700 sq. feet, and each refill can last up to 30 days. For maximum effectiveness, you should replace refills every 4 weeks, and your diffuser every 6 months. Make sure to follow the instructions when plugging in your diffuser, and plug the diffuser in upright.