Petromax HK500 Mixing tube with screw and without

Does anyone know what is the difference between the mixing tube with screw and without it ?

The part in question is 32N

 

@Tomas Vuto

This regulating screw allows you to adjust the mixing ratio and therefore the brightness.

 

Thank you for your reply . My petromax mixing tube has the screw in it, but on the website of the petromax the mixing tube is without it . i will try to save mine because the head of the screw is a little broken

 

The recently manufactured mixing tubes with adjusting screws were of such poor quality that the manufacturer chose the path of least resistance and lowest cost, simply producing mixing tubes without screws.

 

Now i understand why they are different , i will stick with the original . Thank you leo

 

I only have a clone right now, saw the screw, thought it was an adjustment, but then concluded it was just to hold the lower part of the tube in place. Supposedly NOS 829 coming soon and will be interested to see how it was built.