Inspired by Chris Warkocki's idea. Adapters for the Prusa MMU2 spool holders PTFE tube. Adds retention hole and tag for the tube, and they are numbered.
2019/03/22: Added the numbers as separate models in case you want to use the MMU2 to print them in a different color.
Screw a PC4-M10 pneumatic fitting on each adapter with a 5cm PTFE tube.
The author hasn't provided the model origin yet.