The K4200 Series Photo Controls feature stern 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.