Feliway Classic Refill is a plug-in cat calming pheromone refill designed for use with the Feliway Diffuser device (sold separately). It uses a synthetic replica of the natural feline facial pheromone to help reassure cats at home. Clinically proven to help control unwanted behaviours such as urine marking and vertical scratching, it promotes a familiar, comforting environment. Each 48 ml refill lasts up to 30 days, with single and 3-pack options available to suit your household.