ORIGINAL: Hobbsy
The .40a is the newest one and has the new style case, my 2.20 was also in the new style case but had the vent in the backplate.
So the location of the vent varies with model I suppose.
Also, I noticed that the high speed needle spring is very light on my 1.8. So the needle moves too easily. Is there something I need to fix to make it stiffer?