I had a small metal keyring for my (admittedly) few keys, but I never liked how the metal keyrings don't allow keys, fobs, and other necessary items (*cough bottle opener cough*) to lay flat, and the more you put on the more they stick out in every direction. I thought about using string to let them twist freely, but then tying and untying them would be a hassle. Then I thought, ‘I’m a maker, I can definitely design a solution!'

And here it is. Simple, but it works. It can flex freely, be opened and closed easily without coming undone at the wrong time, and lets all of the items on it point in the same direction. My keys are so much easier to put into my pocket now that I'm using it, especially since I like to put them in that little change pocket my jeans have or whatever it's called. 

Anyway, if you're here you probably already know why this can be useful, so I'll stop babbling and get to the important stuff.

This keyring prints quickly and with no supports. This is primarily intended to be printed with a flexible filament (I used Paramount 3D flexible PLA), though there is another version included that will work with rigid filament.

As designed, it will create a keyring that is about 12.5 mm (½ inch) in diameter.

This can be scaled to any desired size, though the Z axis should not be scaled more that 150% to maintain flexibility and minimize inelastic deformation. The length and width can be scaled as much as you'd like, but the width is better left at lower values to maintain tolerances.