What is the smallest dimeter the EX6 can produce?

There really isn't a limit to how small of a diameter our extruders can produce. Using the Spooler and our smallest nozzle(1mm) you can "pull down" the filament diameter by increasing the speed of the Spooler. To a certain extent, it would be difficult to try to extrude and spool filament if the diameter is really small. It will probably be material dependent as well.