The K4100 and K4400 series photo controls feature stem mounting, thermal type, controls with single and multi-voltage models. Thermal type photo controls provide dusk-to dawn lighting control and a delay action, which eliminates loads switching off due to car headlights and lighting. 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.