using the photoresistor induction light intensity comes with the relay, direct control loadDistribution bit sensitivity adjustment, relay set by adjusting potentiometer, when the dark this , the module relay is energized, this , the relay release;12 V input is designed for relay board regulator transistor to sensor Used to make the product more stable and reliable;onboard optocoupler isolation drive relay, the effective protection of the chip to make the product more reliable work;has four fixed hole for easy installationMaterial: metal Color: blueWith lines,Line color is randomModule using the instructions:1, photoresistors module is sensitive to ambient light, generally used to detect the brightness of the ambient light.2, the module when the ambient light is darker than the value is set, the relay is energized, the common terminal and the normally is turned on, when external ambient light is brighter than the set value, the relay is switched off, the common terminal and the normally closed end connected;3, the public side, normally open, normally closed three ports, the equivalent of a dual-control switch, relay coil , public end and often the beginning of conduction, radio, public end normally closed terminal conduction;Supply voltage: 12VDCCurrent: Greater than 100mALoad: 250V 10A AC or 30V 10A DC (the current is less than this range can be used)Size: 5.3cm * 3cm:1PcPackage includes:1Pc xDC 12V Photoresistor Module Relay Light Detection Sensor Light Control SwitchNote: Random color, 't accept the specified color.Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.