I guess the Cooper OVX was used during NGrid's short-lived Cooper phase. They were only used in 400W HPS, though Providence is the only place I've seen them. Elsewhere is just the M-400, though many M-400 are isntalled in Providence too.
OVX were used in NGRID territory's here as well. All were 400 watts.
As for the insulators, those are for the old city wide fire alarm boxes you would see mounted on poles across the city. We still have a few towns here that still have them up but they are slowly going away.
Ahh. Cranston still has them in the older sections of the city but I'm not sure if the boxes still work of if they're disconnected. They really serve no purpose since everyone has a phone at their home and most people have cell phones that can be used to report a fire instead. I'm sure some teenagers pull the boxes for "fun" too. Happens once in a while with the pull box fire alarms at my school.
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As for the insulators, those are for the old city wide fire alarm boxes you would see mounted on poles across the city. We still have a few towns here that still have them up but they are slowly going away.