The pins are marked on the PCB:-

• GND - Connect 0V to this pin.  
   
• IN1 - Controls relay 1, active Low Relay will turn on when this input goes below about 2.0V  
   
• IN2 - Controls relay 2, active Low Relay will turn on when this input goes below about 2.0V  
   
• VCC - Connect 5V to this pin. Is used to power the opto couplers

Specification:-

• High current relay, AC250V 10A, DC5V 10A  
   
• 2 LEDs to indicate when relays are on  
   
• Works with logic level signals from 3.3V or 5V devices  
   
• Opto isolation circuitry