GEREE SRD-12VDC-SL-A DC 12V Relay Module Photodiode 2 Channel Module Combined Photosensitive Sensor Module Light Detection Working voltage: DC 12V . Output Type: AC 220V 10A directly connected or DC30V 10A load. Using the intensity of the light sensing photodiode sensor, comes with a relay, direct load control. Distribution bit adjust sensitivity by adjusting potentiometer setting start relay threshold, when lit this threshold, the module relay close, when the dark this threshold, the relay is released, the relay switch. Small PCB board size: 6.3cm x 4cm.