The cup holder part is designed to snap in to the clamp (and is easy to remove) since you can't fold most strollers with the cup holder attached.

The included STLs are for:

• Clamping to a bar roughly 24-30mm in diameter (to fit the “Baby Jogger City Mini GT2” stroller handlebar)
• A cup/bottle which is 78mm in diameter or less (cup holder height = 96mm)

NOTE: The clamp must be attached with the arrows pointing up otherwise the outer cup holder won't snap in properly.

You can modify any of those parameters in the included Fusion 360 (.f3d) file to suit your needs.

Printing:

• None of the parts need supports as long as you print them the correct way up (zero overhangs)
  • I've included a sample “clamp cup holder all parts.3mf” to illustrate the correct printing orientation, but use common sense
• Materials
  • Print “cup inner” in PLA or whatever you want
  • Print “cup holder insert” in a flexible material
  • Print everything else in PETG or similar WITH 100% INFILL or something will break

Enjoy, I welcome feedback!