This is just a nut with the correct parameters to screw onto the end of a PC4-M10 PTFE connector. I printed the Nuts in PETG. They were easy to screw on and had a tight fit against the plastic container.

Customized version of https://www.thingiverse.com/thing:193647

Created with Customizer! https://www.thingiverse.com/apps/customizer/run?thing_id=193647

Using the following options:

type = nut
head_type = hex
drive_type = socket
head_diameter = 12
head_height = 5
drive_diameter = 5
slot_width = 1
slot_depth = 2
texture = exclude
thread_outer_diameter = 8
thread_step = 2
step_shape_degrees = 45
thread_length = 25
countersink = 2
non_thread_length = 0
non_thread_diameter = 0
nut_type = normal
nut_diameter = 15.5
nut_height = 6
nut_thread_outer_diameter = 10.2
nut_thread_step = 0.9
nut_step_shape_degrees = 45
wing_ratio = 1
inner_diameter = 8
outer_diameter = 14
thickness = 2
facets = 6
socket_facets = 6
socket_depth = 3.5
resolution = 0.5