This is a device designed to control the airflow on tanks. It works well on Vivi Nova, SmokTank, R-Tank, Locking Artemas, etc. Also helps those tanks work on APV's with flush center connector. The Airflow Controller serves to cover the airflow notches increasing the resistance felt when taking a draw off of your device, giving a stronger hit.
The Airflow Controller screws onto the 510 connector of your electronic cigarette. Attach the Controller first and then attach your tank. With the Controller screwed on all the way down the airflow notches are unimpeded. But as you unscrew the top ring of the Controller, it rises up and starts to cover the airflow holes on the tank. You can adjust it all the way until it is snug under the tank.