12 V power input is designed for relay board regulator transistor to provide sensor Used to make the product more stable and reliable; using the photoresistor induction light intensity comes with the relay, direct control load onboard optocoupler isolation drive relay, the effective protection of the chip to make the product more reliable work; Distribution bit sensitivity adjustment, relay threshold set by adjusting potentiometer, when the dark this threshold, the module relay is energized, bright this threshold, the relay release; has four fixed bolt hole for easy installation, Weight: 0.04629707502 Pounds, Manufacturer: detee