Clamshell.

Could this be a revere? This one is missing the lamp and refractor, I think they deliberately took them out and the ballast as well because the store next door didn't want this lighting it. (This was a double pole light and two of the poles them had one clamshell like this one and the other with a refractor and lamp. And the two poles were on the border of the parking lot and the two missing the refractors/lamps both shown over the pother parking lot.