This allows you to upgrade your single extruder MM3 or MTW Create to dual extrusion. Both models are identical other than being mirrored.
If you have a MendelMax 3, your primary extruder is on the Left, so you will need the right side to upgrade. For the Create it is the opposite.
Please note that currently shipping upgrades are designed for our new clamping extruder blocks. If you have the older style block that used set screws to hold the hot end, you will need to print a new extruder body out of ABS. If you are unable to do so, you can either add the Improved Extruder Kit (recommended) or contact us and we may be able to print you the old version for a small extra charge.