BeapharCatComfort Calming Diffuser is a simple and effective solution to reducing problem behaviour in cats, such as inappropriate scratching and urination, or general feelings of anxiety. Beaphar CatComfort contains a copy of the naturally produced cat facial pheromone, which gives a continuous and reassuring message to let cats know that this is a safe area for them to be in. The easy to use plug in diffuser can be placed in any area of the house, and is effective for up to 30 days with continual use before needing a refill. ALWAYS FULLY READ THE PRODUCT INFORMATION BEFORE USE. Each refill is effective for up to 30 days.