This product is a mild form of the Evaporator Cleaner that is designed as a follow-up treatment. Not truly knowing how quickly the bacteria returns in various vehicles, the maintenance treatment will destroy any new bacteria that may start to grow. The directions for using the Maintenance treatment are slightly different. You will access the same place where you originally installed the Evaporator Cleaner. To begin, you will follow the same directions as far as turning on the vehicle to produce condensation before applying product. You will shake the can vigorously and press down on the actuator for 10 to 15 seconds. This will dispense only what you need to refresh the evaporator by cleaning and destroying any new bacteria that started to grow. The Refresher treatment will keep your vehicle's ventilation system clean when you apply it every two months after the original cleaning.