MMU2s rear PTFE holder with Non Passthrough Push to Connect fittings

By default, the holes are too small for the connectors. Inserting brass nuts with a soldering iron unfortunately gets melted plastic into the holes, rendering them unusable. It's a neat idea, though. (edited)

Hey, where I could get colored PTFE tubes?

I like the design and printed it out. But unfortunately the diameter of the inserts were a little too tight (ID 6 mm - the inserts I have got 7 mm) and melted PETG got into the threats while installing them.
Therefore I change the diameter to 6,8 mm. Now it was easy to push the inserts into the holes of the PETG.
Nevertheless a good work & idea.