Comfort Zone Multicat Diffusers with Feliway Helps Reduce the Frequency and Intensity of Tension & Conflict Between Cats in Homes with Multiple Cats. Helps to create a calming environment. Veterinarian Recommended & Clinically Proven Start to See Results in a Week Contains 2 Diffusers, each with a Plug-In Diffuser and a single 48 ml vial in each package. Refill lasts 30 days Use Comfort Zone Multicat together with Comfort Zone Feliway if the cats urine mark and scratch as well as have tension and conflict.