Printrbot Simple Metal Filament Guide

This small piece helps guiding the filament to the extruder mechanism. When the filament is torn at a certain angle, and the spool is not giving away more filament, the filament can bend and jump out of the track. As a result, the printer continues printing without filament.
This small piece should always hold the filament in place so it gets to the extruder in a vertical line.
I will have to do more prints to make sure it really does what I suspect it to.