One of the issue with telescoping ladder is that the rubber feet get damaged, worn, or lost. So I made a reasonable copy. It actually works better than the original.

I think the feet diameter varies depending on the length of the ladder; taller ones have larger diameter feet, so the dimension probably needs to be adjusted and the source file is included for that. Please also publish your design file if you make a change.

Note the extra smaller dot. That side goes on the foot with the aluminum cut-out for alignment.

Printed at 0.25 mm since the appearance did not matter.
Filament was a generic flexible one. Probably should avoid ones that are too soft.