*Size: 138m * 56mm* 18.5mm(LxWxH),weight：120g *Working voltage: 12V *Channel: 8 channel *This relay module is 12V active low. *It is an 8-channel relay interface board, which can be controlled directly by a wide range of microcontrollers such as Arduino, AVR, PIC, ARM, PLC, etc. *It is also able to control various appliances and other equipments with large current. *Relay output maximum contact is AC250V 10A and DC30V 10A. *Standard interface can be directly connected with microcontrollers. *Red working status indicator lights are conducive to the safe use. *Widely used for all MCU control, industrial sector, PLC control, smart home control. Second,Module interface: *VCC: connect 12V power supply positive *GND: 5V power supply connected to the negative *IN1-IN8: signal trigger, active low Relay outputs: There are 12line interface, all interfaces can be directly wired leads, user-friendly. *NO1 - NO8: normally open relay interface and relay before vacant after the pull with COM Normally open interface *COM1 - COM8 Common Interface Relays *NC1 - NC8: normally closed relay interface and relay before with COM, after the pull-vacant