The Feliway Diffuser is a simple and effective pheromone therapy to help you manage your feline friends anxiety levels, keeping them calm and composed. Cats, like people, are complicated creatures. Sometimes they get stressed, or agitated. Perhaps you\'ve brought a new cat into the family, or your cat has returned from a stressful stay at the vets.Each diffuser is supplied with one 48ml vial that lasts 30 days, with replacement 48ml refills sold separately. Whatever the scenario, a stressed cat might behave in any number ways, doing strange things such as scratching your furniture, marking the walls or carpets with urine or even becoming aggressive towards you or other cats.This diffuser unit will help control all this by making your cat feel safe and secure in your home. Simply leave switched on continuously for at least 4 weeks, then re-fill as required.