This is an end cap for a bicycle handlebar. I lost mine, so I made one up. It has been working great, never comes loose.

This is sized for my bike, but re-scaling in a slicer to meet your specific measurements, if necessary, would be easy to do.

If you need this resized, leave a comment and I will post a custom one for you.

I printed in ABS, although PTEG or even PLA will probably be ok.

You can even use this to print off in a color of your choice to customize your bike.