Just plug it in & it works continually for 30 days Each diffuser covers up to 700 square ft Starter Kit includes a 30 day vial for diffuser Contains a clinically tested & appproved synthetic pheromone Recent studies have indicated that Feliway is 90% effective in assisting your cat by reducing and/or eliminating their tendency to scratch and spray urine. Homes with multiple cats can be characterized by tension & conflict, but not any more. Reductions in these types of behaviors is commonly seen within the first 7 days! Feliway MultiCat Plug-In Diffuser has been recently reinvented & it is now better than ever. Designed for homes with more than one cat, Feliway's MultiCat Plug-In Diffuser Starter Kit comes READY to PLUG IN for 30 full days of stress, tension, and urine spraying relief from your cat! Signs your cats may be feeling tension: Fleeing from housemate cats Twitching tail Blocking each other Stalking or chasing Biting, hissing, growling, spitting Signs your cats are getting along: Touch or groom each other occasionally Rub against each other Body contact while sleeping together Directions & Dosage Just screw the refill vial onto the diffuser unit and plug it into an electric socket. The diffuser should be plugged in continuously for best results. Refill vials last for 30 days and one diffuser covers an area up to 700 sq. feet. If you have a multi-story home, you may need more than one diffuser. Do not plug in the diffuser under shelves, behind doors, curtains, or furniture. The diffuser should be totally unobstructed for proper diffusion. For best results, replace the diffuser every 6 months. Ingredients Mother cats naturally emit a pheromone message to their kittens after birth to help them feel safe and secure. This "Harmony Marker" helps maintain a harmonious bond between them. This product contains a synthetic replica of that pheromone and is clinically proven to help reduce tension and conflicts between cats.United States