This is a remix of https://www.thingiverse.com/thing:3027499
I started with the referenced Thing, but it didn't fit the larger ring pulls on some cans. So, I imported the STL into SketchUp and enlarged the business end.
My wife has passed several along to friends, especially the older ladies in our neighborhood who find them exceptionally helpful.
Like the original, it uses a 10mm by 1mm rare earth magnet so it can be hung on a refrigerator. I use OctoPrint on my printer for control and installed its Multi Color add-in so I can setup an automatic pause for installing the magnet.
I set up a gcode file from Simplify3D to print three at a time.