Harmony Pet Calming Spray for Cats is fast-acting. This technology uses P.E.T. pheromone to help calm cats by mimicking the maternal pheromone from momma cat to soothe her kittens. This technology helps the pheromone quickly enter the nasal cavity, providing short term relief. Cats of all ages recognize this calming pheromone for life. Helping cats live in harmony wherever they go.