lens-cap
thingiverse
I tried to document what you need to do to adjust it to fit your needs. quick way to replace 3 lens caps for Telescope of varying sizes
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With this file you will be able to print lens-cap with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on lens-cap.