This is a rear light on a fire engine I bought. It is a Unity but not sure which model. I think it is missing a part as there is a screw hole on the top. There would have been two of these but the second is missing, so I'll need to match this one.
This is a model S6 AG Series Decklight. The part missing on top is for the name plate that would identify the model. This is an older version from the one we currently make but still very similar. We no longer carry red lamps. Also there should be a switch to turn the light on and off on the light itself. From pictures can't tell if that is missing. That is using the Round bracket. http://www.unityusa.com/AG-Series-6-Decklight-S6_p_1822.html