FELIWAY Optimum is a new patented pheromone discovery and is the best FELIWAY answer to help reduce the most common signs of stress in cats. It helps with more signs of stress in more situations and calms cats better than ever; it helps reduce scratching urine spraying (peeing) tensions & conflicts among cats general fears and reactions to changes. This new discovery backed by FFELIWAY s 25+ years of feline stress expertise delivers advanced calming messages helping your cats feel more comfortable at home than ever before. When surveyed 93% of cat owners reported enhanced calming for their cats when using FELIWAY Optimum. FELIWAY Optimum s heated diffuser and refill provide calming pheromones continually for up to 30 days in a 700 square foot area. We recommend using an additional diffuser if the room is bigger than 700 square feet. We recommend plugging in the FELIWAY Optimum diffuser in the room where you cat spends the most time or where conflict among your cats happen most frequently. Try no