This is a simple connector for your PTFE/Bowden tubes.

Print these: PTFE split 1, 1x PTFE split 2, 1x PTFE split hook, 1x

After printing insert a M4 nut into the cutouts on the top, then "screw" the Bowden tube trough the nut while making sure to press on it. If done correctly the outer wall of the bowden tube will be threaded and locked into the coupler. Look at the pictures for an example.

*I recommend to drill out the Bowden tube (with a 2mm drill) that is inserted in the coupler, this makes the path more smooth since the M4 nut makes the inner dimension smaller.