Feature: Power indicator (green),relay status indicator (red) SMD optocoupler,driving ability,stable performance; trigger current 5mA Fault-tolerant design,even if the control line is broken,the relay will not move Interface design is user-friendly,all interfaces can be directly connected by wiring terminals,very convenient Specifications: DC+:Connect to Positive Power Supply (3.3V) DC-:Connect to negative pole of power IN:Low level control relay pulls in Relay output: NO:The relay is normally open interface, before the relay is closed,it is left unconnected.After picking up,it is shorted to COM. COM:Relay Common Interface NC: Relay normally closed interface,short circuit with COM before pull-in relay Size:5.6x1.2cm/2.2x0.47inch Note: Please allow 1-3mm error due to manual measurement. pls make sure you do not mind before you bid Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package Includes: 1x 1 Channel Relay