The original model by fluf was good but 2mm too tall and often fell off, so I shortened it and also made a few personal tweaks. Chamfered edges, higher model resolution (the original suffered from being pretty low poly), and easier to slide on but stay on. 

I have the Modi and Magni, which measure 67mm tall, with a little push I can fit this model on both sides of the stack and have it hold together firmly, while not interfering with the rubber feet. 

Using Bumpmesh by CNC Kitchen, I added a slight wood grain pattern to the model, for those interested in printing it with woodfill filament.

I printed with iSanmate Sandal Wood PLA.