The K4200 series photo controls feature stem and swivel mounting, with thermal-type controls. thermal-type photo controls, which are available in single or multi-voltage models, provide dusk-to-dawn lighting control and a delay action, which eliminates loads switching off due to car headlights, and lightning. the thermal-type controls feature a cadmium sulfide photocell and a sonic welded polycarbonate case and lens to seal out moisture. the design utilizes a dual temperature compensating bi-metal and composite resistor for reliable long life operation over ambient temperature extremes.