As an exercise in learning Fusion 360, I have made this bottle neck that conforms to the PCO-1881 standard, used in many modern 2L bottles. If you just want to interface to bottles, I suggest you use laird's model.I don't know why anyone would want to print this thing, but if you were determined to, the best way is to print it in two halves horizontally and glue them together. Printing in one piece may be problematic because of the overhangs. You will need support for the interior arch. I have not provided a split model, but with most platers you can do a quick and dirty split by copying the model, rotating one, and dropping both below the bed so that the bed is at your desired parting line. Place the parting line so that it is 90 degrees from the thread start.