Allen Bradley 800 T psd16 c
There should be a diagram right on the label of the pilot light itself.


The dual inputs is because it is for a system in which you have a common circuit, usually connected to a momentary push button somewhere, that you press to illuminate ALL of the pilot lights at the same time, to test whether or not the lamp is burned out. So (typically) your regular indicator circuit would go to terminal 1, the Test circuit would go to terminal 3 and the common (neutral) would go to terminal 2. There are diodes on 1 and 3 that prevent the circuits from back feeding to each other.