This is a filament strain relief for the Raise 3D N2 series extruder head (photos show it in an N2Plus).
It is designed to accept 4mm OD pneumatic push fit connector with an M6 threaded connection. Like this one http://www.banggood.com/4mmTube-Connector-Union-For-3D-Printer-Filament-Guiding-Teflon-PTFE-Tubing-p-1003373.html The 5mm bore must be pre-tapped to M6 before attempting to install the threaded connectors.

This part was modeled in Autodesk Inventor 2015 with dead sized cavity to ensure snug fit, you may need to tweak the model depending on your specific machine dims. This part will take about 12g of material to print. Orient upside down on the print bed, Reccormend printing solid at 150-200um layer height.

Please Like and Share - Catch me on the forums at http://forum.raise3d.com