Pentel BK77 cap

Alternative caps for my favourite inexpensive pens: Pentel BK77. I lose caps too often and I don't want a partially used pen to dry out. Hence these caps I've designed after measuring originals and some trial-and error.

12d0 (outermost diameter, at bottom lip: 12.0mm) version is a tight-fit one, requiring a bit of force to both put on and take off. Makes them harder to lose accidentally!
12d5 (outermost diameter, at bottom lip: 12.5mm) version is a loose-fit, it clicks but is easy to remove just like the originals.

This is a quick hack, clicked in Tinkercad after measuring original cap (and some trial-and-error), so it has some visible artifacts of boolean operations. I'll clean it up later. It still prints smoothly.