When doing retraction with the Ultimaker the quick connect on the extruder allows a bit of play.
This clip tries to eliminate this play.
Very similar to LawrenceJohnston shim, but this one is secured with a small zip tie and tries to grap the connector even better.
To be used with a small zip tie with width of 3mm. The OpenSCAD file is parametric, so adjust if you have a different one.