Provides instant and authentic fragrance. Odor neutralizing formula keeps the car fresh and fragrant. Discrete unit clips to the air vent - no need to hang from the rear view mirror. Can also be clipped to window air conditioner unit vents. Each package contains 4 vent sticks contained in a resealable pack. Can be used all at once or 1 at a time. Up to 2 weeks per stick product life.