Summary 16/07/2015: Now Customizer is available for this design, so you can create your own STL without editing the scad file. I hope you enjoy. This is just a 5 minutes design that everyone can make, but still I find it very useful. You can create your own caps for almost every bottle. They fit quite well. I tried to label the variables you can modify. https://youtu.be/nqnh0AfhVDk Instructions Measure the outerRadius and border of the bottle. Be very precise and still I would add 0.5mm for outerRadius and 0.2mm for border, but it will depend on the size of the bottle neck. There are no strict requirements for printing, you can check the screenshot of my Cura settings.