Canon lens cap. Fits well on EF and EF-S lens.
Please add comments to understand your experience with the thing and ideas for improvement!
Two STLs: first with inner dome is perfect for fast printing without support structures. Second (on photo)- with flat bottom needs support and 1 more hour of printing. Enjoy!
Jenny (Ultiamaker 2 clone)
First image do not need support (inner dome) - just print it bottom up.
Second image - with flat bottom needs support. I like printing ABS but should be careful to apply scaling. As support material (I have 2 extruder printer) I use SBS that perfectly can be separated from ABS immediately after print