Here's a snug-fitting XLR plug for your Onewheel. It fits all models. Printed in TPU, with a .4mm nozzle, you get a very clean plug that's low profile, while still having a small finger holder to remove it when necessary.
If printed correctly it does not fall out and fits snugly.
This plug should do pretty well to keep water and dirt out of your XLR charge port on your Onewheel, and was developed as an offshoot of our new CNR cable using a very similar model (except that it has wires coming out of it to connect to an external battery.).
EDIT: I adjusted the model to make it fit a bit more loosely...as the XLR port on various Onewheels can fit differently, and in some cases be too tight and hard to remove.
Cheetah, Sainsmart, Ziro TPU for best results
Print with supports, but remove supports from the holes the pins plug into (not needed there). Print with the flat side on the build platform. TPU gives the best result. I used a .4mm nozzle and .2mm layers.