This is a replacement for the bottom pin in Ortlieb QL3.1 pannier mount.

To use this pin, one must replace the original socket head cap bolt (M5x30) with a countersunk bolt (also M5x30).
This allows for a thicker material around the head of the bolt, so that an item printed out of filaments much weaker than Ortlieb's plastic will endure same stress.

Mine got ripped when I fastened the pannier, heard the customary click, and went on with riding my bike, but I accidentally fastened only one of the top pins rather than both of them. So my bag fell off on the first larger bump, sending the ruptured part into oblivion. So the replacement is likely not to follow all dimensions of the original, but operates as expected.

Printing the part is faster (and cheaper) than sourcing a new mount - sadly Ortlieb does not seem to provide any replacement parts.

I printed mine out of ASA, 0.2mm layer Double check your printer dimension accuracy: the shaft of the pin shall be 10mm (as in the .stl file) to fit perfectly.0.5mm nozzle, with no brim or raft.
Double check your printer dimension accuracy: the shaft of the pin shall be 10mm (as in the .stl file) to fit perfectly.