I needed to check a plastic bottle neck thread. I measured it and according to the internet it was a 24/415 thread. I downloaded a thread model and stuck the top on. Then printed it to actually check it would fit my bottle.

It did. I then made a screw on funnel for the bottle [https://makerworld.com/en/models/530906#profileId-447717](https://makerworld.com/en/models/530906#profileId-447717)