Some of the end caps on the plastic wrapped poles that we use for building horse jumps at home were broken. I couldn't find any that matched their diameter, so I decided to make my own. Really simple model and you can scale it up or down a bit if you have a special diameter that you want to use it for. 

Outer measurements are 58mm high and 106mm wide. Sides and bottom are 4mm thick, so that makes inner measurements 54mm deep and 98mm wide.

In Freedom™ units that is 2.28 high by 4.17 wide (outer). Thickness of 0.16. Meaning 2.12 deep by 3.85 (inner).

Print it on the flat side, no brim and use PETG if used outside. This will also make it less brittle. 

Enjoy!