The lenght of the bowden and the stifness of the fillament can influence the quality of the docking of the magnetic 2th head. This adjusatable feedermount gives you the option to change the angle of the feeder, and the pressure it passes on to the head. Main project info here; https://magnetic-tool-changer.com/ Questions? ask here; https://ultimaker.com/en/community/48788-ultimaker-mark2-the-smart-dual-extrusion-upgrade The long mount can be used on older Ultimaker2's that still have the hole for the 2th feeder motor in the backplate.