I suspect you are talking about the HC-1 Type D color light signal.
It is built out of brass(painted silver/black)
There are very nice for the price. They are almost as good as the Tomar signal, but do not have the instrument box like the NJ Int signals.
There is the ladder/platform. It is all metal, but is not as finally detailed as the Tomar or NJ Int signals.
On the layout, they look good. If I had an unlimited budget, I would use the NJ Int Type D signal. As it is, at least I have a start on a good working ABS signal system. I have two of their detectors and will be installing 6 more after the 1st of the year. Being IR, they are not affected by room light like the Logic Rail detectors, and I had to do no ‘detectable’ wheel set conversion.
Just a slight correction, we offer IR and non-IR (i.e. photocell) versions of all of our products! The non-IR versions DO require sufficient overhead lighting to function properly. The IR versions, of course, do not.