Intermatic K4321C 120-Volt Fixed Position Thermal Photocontrol with Wall Plate Thermal photocontrol on a face plate for effortless dusk-to-dawn ON/OFF control of exterior lighting, street lighting, parking lot, pedestrian pathway and landscape lighting For control of exterior lighting, street lighting, parking lot, pedestrian pathway and landscape lighting Smart delay feature prevents unwanted OFF switching of lights due to passing car headlights or lightning Features a cadmium sulfide photocell and a mechanical bimetal switch 3/8" - 18 NPSM, 3/4" long stem with locking nut and washer gasket