Light bulb ball chain pull/ceiling fan pull. Print both parts with brims. Ball chain feeds through the base & then is capped with a connector. The base pushes very snugly into the bulb part, can be pulled apart with chain connected or with pliers. The base has a 2.5mm chain hole & the large version has a 3.1mm chain hole. A 3.4mm connector should work with both sizes. This is sort of a remix of Simon Pratt's Light Bulb Light Pull model—I took the base from that model & the bulb from another, and I liked the concept of the 2-part pull, just changed it from a screw to a plug.