The K4100 & K4400 series photocontrols feature stem mounting, thermal-type, controls with single and multi-voltage models. thermal-type photocontrols 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 bimetal and composite resistor for reliable long life operation over ambient temperature extremes. these models are California title 24 compliant.