This clamshell was an oddball when I first found it, in a parking lot behind a candy store in South San Francisco, CA, a suburb of San Francisco. I have pondered who made this luminaire, since I have never seen this luminaire anywhere else. Now thanks to some literature, I know for sure. This is a Wheeler Fullerton large-sized clamshell for 700-1000 watt mercury lamps, like Westinghouse's OV-35. Wheeler Fullerton also made small 100-250 watt sized ones and 400 watt sized ones. Ones with integral ballasts were also made with larger slipfitters for the ballasts to fit in. Wheeler Boston was a small manfacturer based in Boston, MA which made outdoor light fixtures, reflectors, and streetlights, mostly incandescent types but some mercury ones were also made. Wheeler streetlights (usually radial waves and quarter moons) were very popular in New England, but are rare in California although I believe some Wheeler radial waves were used on some of California's streets before WWII.
