My first ever swimming goggles have been following me for almost two decades before the flexible middle part gave up and started crumbling...
About 18 years ago, I bought myself a pair of swimming goggles. I had bben using them every time I went to the swim, which I did a lot at the time.
As I grew older, I did not use them so much, and they ended up in a drawer.
Until one day, when I was going to the swim again. I picked up by beloved swimming goggles, and they were still looking mighty fine. EXCEPT the little, thingy that goes over the nose, so I decided to enter the design into OpenSCAD.
At first I printed the thing in PLA just to see if I got all the measures correct, then I attached it to the goggles and dipped it into hot water to make the PLA bendable. Looks good, but the PLA i a bit too brittle, that's why I went on and printed it with flex filament - it fits excactly like the original part and it shall be exciting to see how long this one will last - anyway, now I can always just print another.
I have provided the OpenSCAD source just in case anybody wants to tinker and make one to fit their own swimming goggles.
Or... you could just press the "Open in Customizer" button and design one to fit your own swimming goggles.
Just print out the thing using best resolution (layer height) possible and 70-90% infill.