Harmony Pet Calming Collar for Cats uses P.E.T. pheromone to calm cats naturally. This pheromone technology mimics the maternal pheromone from a momma cat to soothe her kittens. Cats of all ages recognize this calming pheromone for life. The continuous release of the calming pheromone helps provide relief from anxiety and stress for up to 30 days. Helping cats live in harmony wherever they go.