Looks like new.
Does your transformer have only one sound option (whistle) but your trains have Bell as well? This is the button you need to add on to your Lionel trains to be able to activate that secondary sound. It also works with American Flyer.
If you need INSTRUCTIONS for how to hook this up, please let us know.
NOTE: This switch is designed for use with common ground wiring. It is not to be used with a Lionel #6-4690 Type MW transformer. For proper installation, refer to RailSounds instruction manual.
As you can see, it comes with wire.