From the Manufacturer
Place the signal along the mainline on your Lionel railroad, and passing trains will automatically cause the lights to change from green to red. Once the train has cleared the signal, the lights will change back to green.
Make sure this fitsby entering your model number.
Automatically resets to green when train clears its block
Lights change from green to red when train moves through its block
Package Dimensions: 10.16 L x 5.842 H x 10.16 W (centimeters)
Country of Origin : China