Squeeze Bottle Cap (Parametric)
I use these Wilson Candy Making squeeze bottles for a lot of things around the shop (this one is for paint thinner), but the caps always seem to get lost or damaged -- and even when they're not lost or damaged, they're tiny and tapered, so they're not very easy to remove. So I made a replacement cap to solve both those problems.
The ridges in the printed plastic hold the cap on tightly.