This is two versions of an adapters set to be able to upgrade you pinball game speakers to JBL Stage 502 speakers. The adapters fits to Stern pinball games (So far tested on: Munsters, Black Knight, Ghostbusters and Walking Dead, but they will probably fit in many other Stern games as well)... Print 4 parts (of the one with "slits" or the one without, depending on how the current speakers are fastened).
You will need to add 4xM4x20 and 4xM4 Nuts / speaker.
Mount the M4 screws in to the adapters and then install the adapter with the old speaker screws. Now mount the new speaker on the adapter...
After print you need to drill out the 4mm holes that is used to hold the "new" speaker with the M4 screws.