On some of our Heng-Long tanks the 'on/off' switch for the smoke generator is located underneath the tank but will be marked as 'A,B or C'.

There will only be two positions available, one 'on' and the other 'off'. it will become quite apparent when the smoke generator is on as you will be able to hear it working.

It does not have to be switched off after every use as the main 'on/off' switch will over ride the smoke generators switch.