Description : 1. The module uses genuine quality relay , normally open interfaces Maximum load : AC 250V/10A, DC 30V/10A; 2. The power indicator (green) , relay status indicator (red) 3. Module size : 50mm * 26mm * 18.5mm (L * W * H) 4. Has four mounting bolts holes , hole 3.1mm, 44.5mm * 20.5mm pitch Module Interface: 1. DC +: positive power supply DC 12V 2. DC-: negative power connection 3. IN1: 1 channel signal to trigger the end , you can set a high or low level control relay 4. IN2: 2 -channel signal to trigger the end , you can set a high or low level control relay Relay Outputs: 1. NO1: After a relay normally open interfaces , relay before floating, shorted pull with COM1 2. COM1: 1 relay common interface 3. NC1: 1 relay normally closed port, COM1 relay shorted before and after the pull- vacant 4. NO2:way normally open relay interface, the relay before floating , pull back and COM2 short 5. COM2: 2 Common Interface relay 6. NC2: 2 -way normally closed relay interface relay short front and COM2 , pull vacant post Note: This relay will be triggered by DC 12V, can not trigger with the arduino signal at 5V. Package Included: 2*DC 12V 2 Channel Relay Module With Isolated Optocoupler High and Low Level Trigger