My APO only has one dovetail shoe and I needed more mounting options. This ring can accommodate three (lightweight) accessories. Fits telescopes with a ~115mm outer diameter. -Update: Ooookay, this is why I always mark my stuff as a WIP. The screw holes are too small, the hinge fused to the rest of the ring, and my measurements for the dovetail shoe were embarrassingly wrong. Back to TinkerCAD to try and salvage this design... -Update 2 (v1.1): Fixing the model took less time than I thought. I'm going to fire up a test print, but in the meantime I've updated the STL here for the intrepid among you to try out. -Update 3: I've also uploaded a standalone dovetail shoe. It makes a lot more sense for me to use that as a test print. 55 minutes instead of five hours, and a fraction of the weight. -Update 4 (v1.2): Screws fit snugly, but the shoe is still undersized. Tweaked and uploaded the files... again... -Update 5: Successful test fitting of the standalone shoe. Time to print the whole ring. -Update 6: The ring is a tiny bit too loose and the shoes are a snug fit, but the former was fixed with a rubber band and the latter just needed some elbow grease. All in all, it was a fun learning experience and I now have more accessory shoes than I know what to do with.