This is a 5V 4-channel relay or four channel relay module interface board, and each channel needs a 15-20mA driver current. It can be used to control various appliances and equipment with large current. It is equiped with high-current relays that work under AC250V 10A or DC30V 10A. It has a standard interface that can be controlled directly by microcontroller.

• Size: 75mm (Length) * 55mm (Width) * 19.3mm (Height)
• Weight: 61g
• PCB Color: Blue
• There are four fixed screw holes at each corner of the board, easy for install and fix. The diameter of the hole is 3.1mm 
• High quality Songle relay is used with single pole double throw, a common terminal, a normally open terminal, and a normally closed terminal 
• Optical coupling isolation, good anti-interference.
• Closed at low level with indicator on, released at high level with indicator off
• VCC is system power source, and JD_VCC is relay power source. Ship 5V relay by default. Plug jumper cap to use
• The maximum output of the relay: DC 30V/10A, AC 250V/10A