Well, a Nex18 dummy plug only plugs into a Next18 socket, and E24 dummy plug only plugs into E24 socket. How can they be interchangeable? You can't jam a Next18 connector into E24 socket or vice-versa. Same goes for any other dummy plug - they only work with a mating connector. But functionally they all work the same way - they connect track power to the motor and also to the headlights.
