Willis Lamm's Traffic Signal Collection (And Street Lights Too) Clicking on a picture will bring up a larger view in a new window.   Westinghouse OV-10 "Clam Shell" Street Light

"Clam Shells" were a style of mercury vapor luminaires that were popular in the 1950s and '60s. Westinghouse's first widely used remote ballasted mercury vapor light was the OV-20. Shortly afterwards the OV-10 hit the streets, primarily on smaller streets where lower wattage lamps were desirable. The OV-20 typically came with 400 watt MV lamps. OV-10s typically came equipped with 100 to 250 watt MV lamps. Westinghouse later produced a "Power Pack" version of the OV-10 that had a ballast compartment that fit behind the reflector and was integral to the mounting hardware. Eventually the reflector and refractor were integrated into a cobra head design, known as the OV-12.

Top of the reflector.

Bottom view of head and mount.	Reflector sized for smaller MV lamps.
Holophane refractor ID and markings located on lip.	Installed in the collection.