The K4000 Series Fixed Position Mounting Photo Controls are thermal type Photo Controls that fit into a standard outlet box, post lamp, or wall pack. The Photo Controls provide dusk-to-dawn lighting control along with 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 bimetal and composite resistor for reliable long life operation over ambient temperature extremes.