The Form 175 is the Form 400's little brother. Unlike the Form 400 which was very popular, the Form 175 found very limited use. It found limited use likely because in the 1950s most streetlights on residental streets were still incandescents, and mercury vapor was usually the reserve for highways and major roads, and also at the time mercury vapor lamps, being relatively modern back then especially with quartz arc tubes, were very expensive, so citywide use of mercury vapor lamps was probably not feasible in many areas. Anyway enjoy the pics!
This Form 175 was used as a 100 watt mercury streetlight prior to being taken down, the Ken-Rad 100 watt mercury lamp shown on the HID page came with this!
