You are looking at an original Lionel CTC lock on. This one is used in C6+ condition. A little wear, so not quite excellent.
It is just what you need to get power to the track from the wires coming from your transformer. This one is vintage, clean, and working. It may show a little wear and oxidation as it is used. The picture is a shot of one of them, all in similar condition.
Also good with ANY three rail TUBULAR track such as Marx, K-Line, Williams, etc.
Please supersize the pictures to see it all up close and personal.
You know that the tubular track is now being discontinued by Lionel, so you have to get it any way you can.