This is a Bowden Tube coupler which uses (2) PC4-M10 pneumatic fittings on both ends. 

I designed it so I could easily open up the tube which goes into my printer enclosure and connects to my BMG extruder. 

There are two versions of the “D” part:

• The D1 type parts can use an insert printed in TPU.
• The D2 type part does not need the insert.

I think the TPU insert could be improved to actually seal the tube, but I don't really need a seal for my enclosure, but it may help a little to keep things dry. To help it “seal” though, let the end of the Bowden Tube extend by about 8mm from the face of the “B” part (which screws into the “A” part), that is shown in the 2nd to last pic. 

A flat head screwdriver will be needed to screw together the A and B parts, which retain the “C” part with the internal threads and large hole.

Some of the parts will need to be rotated for printing without supports (recommended).

(imported from Printables)

If you find these models useful, please post a like or a comment with some pics of your prints. 

You can find the other things I'm working on at my blog here.  You can also follow me here or on Printables, to see what new stuff I post.  If you would like to support my work, you can Buy Me A Coffee using this link:

https://www.buymeacoffee.com/mystoopidstuff

Thanks for looking!

Updated 2/22/2022 to correct a problem with the PC4-M10 threads. The new version is 
"5C".