# How do I set up a 2 in 1 out extruder system in Marlin

Hi I recently upgraded my CR-10S motherboard to the SKR 1.3 with TMC2208 drivers, in addition, I added a 2 in 1 out extruder system, but I am unsure of how to set it up in Marlin. If anyone could provide me a list of the lines of code I need to comment / uncomment / change, or any other advice it would be greatly appreciated.

• Did you get it to work with the hints that are given? If so, please accept the answer to prevent the question form popping up in the unanswered question list. Thanks! – 0scar Jul 12 at 9:12

You need to change the amount of extruders in the Configuration.h:

Set 2 extruders by defining:

#define EXTRUDERS 2


Define that you have a single nozzle:

#define SINGLENOZZLE


If you want to switch filament during a print, you need to write tool loading and unloading (tool changing) scripts for the slicer you use, also do print a filament prime/wipe tower that is large enough to purge the filament to prevent color mixing.