Harmony Pet Litter Box Diffuser for Cats is unplugged and portable. Each diffuser cartridge continually releases a safe pheromone for cats for up to 14 days, providing 1 month of calming benefits when they need it the most. The P.E.T. pheromone mimics the maternal pheromone from momma cat to soothe her kittens. Cats of all ages recognize this calming pheromone for life.