Anybody care to explain the relative rarity of Unidors?....i can only recall Meredian,MS being the lone place ive seen a great deal of both the small & Large versions.
They could have been more higher-end "upscale" cobraheads, kinda like how Hubbell cobraheads are today. High quality but too expensive for mass-use. The UniDors are pretty unique, with all the "guts" mounted onto the door (except for the PC socket and terminal block of course).
They used to be pretty common here. Especially the older downtown part of Brampton, Lots of Unidors, also lots of pemco fish heads. I found out This street originally used Unidors on those fixtures from the creek up ahead all the way to the 407 ETR highway! Now theres only a small stretch of them left, and almost all of those remaining old fixtures mainly have OVXs now. Quite a few of the R47s still too. and I can only remember as far back as there only being R47's, an OV-25 (down the street before construction took out a small area of them and A model 25 on those arms. I guess the R47's are what replaced the Unidor 400s.
Both Unidors used to be pretty common in my neighbourhood. Most were installed in the late 70s as either part of new residential developments or to replace mercs in the case of the main roads. They were killed off by LED starting last year. I believe the last Unidors got changed out to LED this summer.