This is a PTFE Tube Connector for PC4-M6 fitting, and a 2mm ID, 4mm OD Boden Tube, for going through a 1/2" hole through 1/2" MDF. I designed this in Fusion 360 to route my filament through the shelf where my Prusa Mini sits.
Here's the link to the PTFE Tube & Connectors that I used with it: https://a.co/d/gb7IKSc
The author marked this model as their own original creation.