I keep my keys on a carabiner, which I keep clipped onto my belt loop. I often drop keys when clipping or unclipping the carabiner from my belt loop. However I frequently need to remove or add keys to the ring, so I don't want the keys to be too difficult to switch out. Hopefully this design works to my liking. Update: After a couple days of real-world use, I've uploaded a heavier-duty version, and one scaled just a bit larger.Designed in Inventor 2011; printed in PLA on a Replicator 2 via Makerware 2.2.2.89 with "standard" settings; 3 shells, 100% infill, 234 degree extruder; 14 minute print time. Heavier version took 23 minutes to print.