When my roommate got his new motorcycle, he was terrified of dropping it. I wanted a quick swappable print that would protect the ends of his handlebars and make him a tad more confident in his great new transportation. They needed to fit snugly and not get in the way. He has been using these for an entire year now, and he's happy with them!
I would print these in PTFE since they'll be outdoors and need to be a bit flexible for the fit. They sit pretty snugly in there, so if the stalk breaks off and gets stuck in there, you just have to get a hook in there and pull it out.
The author hasn't provided the model origin yet.