STP For Over 60 Years, And For More Miles Than Anyone Can Count, STP Has Been One Of The Most Trusted Names In Automotive Care Car Enthusiasts, Do It Yourselfers And Professional Racers Rely On STP Oil Additives,Fuel Additives And Brake And Power Steering Fluids To Keep Their Vehicles Running Better Longer. And They Count On STP Automotive Appearance Products To Keep Their Vehicles Looking Great, Too. STP, Headquartered In Danbury, CT Is Part of Energizer. STP AUTO AIR-CON CLEANER Fast and easy 10 minute job DIRECTIONS Shake well before use. Start engine and set A/C into internal circulation at full power. Open all vents. Ensure all seats are at upright position and place can behind the front passenger seat. Activate the can by pressing down on the valve. Close the door and make sure all windows are also closed. Wait 10 minutes until the can is empty. Then switch off the A/C system and engine. Open all doors and windows to ventilate the vehicle.