Part of a project to build a printable microphone, but thought it could be useful for someone separately. https://github.com/jonnor/projects/tree/master/printable-electronics Has a very satisfying snap when entering jack, quite secure. Tested with ProtoPasta Conductive PLA. Resistance of ~500 ohm per terminal. This is actually quite good, as the contact resistance of this filament when printed is around 300 ohms. A lesson learned during creation is that ProtoPasta Conductive is unsuited as a spring. Way to soft and prone to breaking. Print one of each STL.The two halves should be printed flat side down. You may want to scale the traces and spring down to 90% height, for easier fit. Files with "cond" in the name should be printed in conductive material. No vitamins needed! Update 1, July 16: Added better spring. Tested successfully in functional prototype of a microphone.