These may be found by searching for Photocell Light Control. Beware of cheap products or those with short warranties. I unknowingly purchased some with a nine month warranty and they all burned out in 6 months. I think they were RCA or something similar fro Home Depot. Previously, I had always used Leviton light controls and they typically work well, last a long time and are reasonably priced. I have some Leviton products that are over 20 years old that still work well long after some cheaper brands died. Leviton and other reputable wiring products can easily be found at electrical wholesalers. Some serve the public but other don't.