Twist Lock Dusk to Dawn Photocell replaces all brands of photocells for your area light. It works on mercury vapor, high pressure sodium or metal halide fixtures. This photocell locks in place with a simple twist.. Exterior Lighting Accessory Type: Photocells. Outdoor Lighting Features: Weather Resistant. Product Weight (lb.): .25 lb. Returnable: 90-Day. Product Depth (in.): 2.5 in. Product Height (in.): 2 in. Product Length (in.): 2.5 in. Product Width (in.): 2.5 in. Exterior Lighting Accessory Type: Photocells. Outdoor Lighting Features: Weather Resistant