Creality flexible TPU Extruder with metall thread for Ender 2, Ender 3, Cr-10

The only solution that really holds the pneumatic connector in place for longer than 3 prints.

Brass thread insert (M6 x 6):

https://www.aliexpress.com/item/100pcs-50pcs-20pcs-m1-4-M2-M2-5-M3-M4-M5-M6-M8-Braas-insert-nut/32961915881.html?spm=a2g0x.10010108.1000001.12.130e7af97lWhte

The brass insert can easily be pressed into the plastic with a soldering iron.

https://www.youtube.com/watch?v=x2SYHr0kyTE

Works with these pneumatic connectors (PC4-M6):

https://www.aliexpress.com/