Kanger has continually updated the airflow control valves making it very confusing as to what valve fits what.
Below I will try to make it simple.
The Kanger Airflow Control Valve - "V1" "V2" and "V3" all fit:
Protank 1, Protank 2, Protank 3, Aerotank, Aerotank 2, Genitank
The Kanger Airflow Control Valve - "Mini V2" and "Mini V3" fit:
Protank Mini, Protank Mini 2, Protank Mini 3, Aerotank Mini, Genitank Mini
The Kanger Airflow Control Valve - "Mega V1" and "Mega V2" fits:
Aerotank Mega, GeniTank Mega
Please check the pictures and select which one you want on the bottom of this page (scroll down)