This is an out-dated version that I have never actually printed, I would recommend V2 here http://www.thingiverse.com/thing:5689 **This is a simple carabiner to be used as a keyring. (this will not hold alot of weight, so don't try mountain climbing with it!)

Print the carabiner out on a 3d printer. Then coax the outer long side, to the inside of the carabiner, so that it will clasp together.

Notes: There are 3 versions of this carabiner. The first version (carabiner.stl) might be too hard to bend into place, but will be stronger than the other version. The second version (carabiner2.stl) will be easier to bend, but not as strong. The third version (carabiner5.stl)will be the easiest to bend, and doesnt have any overhangs(I would recomend this one). I cant take credit for the third one, it was a design by ssd (in the comments), and the carabiner by Torleif (thanks guys).I would appreciate the feedback to help me make the design better, since I dont have a 3d printer. I have also included the google sketchup files so that you can modify my design to make it better.

Update: I realized after putting up carabiner3.stl, that it wouldnt run through skeinforge, so I have uploaded a new version carabiner5.stl, that should work just fine. Sorry for the inconvience.