Gardena compatible fitting for a cap with a 63mm sawtooth thread. Works on Seas to Summit Watercell X water bag.
Use a more heat resistant material PETG/PCTG/ABS/… for the cap itself. Use TPU for the seal.
Assemble
Place the seal in the cap. Make sure to push the slanting side into the cone, so that the flat side faces you.
Last piece is the Garden compatible nozzle itself. You can print one yourself or buy them quite cheaply. You need the ½" type (Gardena style fitting with ½" external thread - I bought these from Amazon).
The author marked this model as their own original creation.