This Intermatic K4136M thermal type photo control provides dusk-to-dawn lighting control of security lights, billboard lights, walkway lights, parking lot lights, and flood lights and features a delay action, which prevents your lights from switching off due to lightning or car headlights. Functioning in temperatures from -40 degrees to 158 degrees Fahrenheit, this stem and swivel mounting photocell features a light level slide and a standard 1/2-inch stem and 6-inch leads for safe and secure mounting. The unit is California Title 24 compliant and works on 120/277 volt systems. This photocell not only comes with a nut and a washer to complete installation, but also features a sonic-welded polycarbonate case and lens to seal out moisture, ensuring your unit is protected from the elements. With a dual-temperature compensating bi-metal and composite resistor to withstand temperature extremes, this photocell is a great choice for your photo control needs.