Harmony Pet Calming Collar for Dogs uses P.E.T. pheromone to calm dogs naturally. This pheromone technology mimics the maternal pheromone from a momma dog to soothe her pups. Dogs 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 dogs live in harmony where ever they go.