These are a 2 part Z-axis cover which are very easy to install. Just place the axis cover on, and fit the insert in place.
Compatibility:
I have a MK3s+, so these were designed around this version. Your mileage may vary on other versions.
Printing:
The author remixed this model.
I liked the style of the model by layer.works which covers as much as possible for the z motor, but wanted to try a version that can pop into place without disassembling anything.