The IR Relay Shield utilizes four high quality relays and provides NO/NC interfaces that control the load of high current. Which means it could be a nice solution for controlling devices that couldn’t be directly controlled by Arduino’s Digital I/Os. The onboard infrared receiver allows you to make infrared remote control fan or other smart home project. It can be plugged onto the Arduino UNO R3 / Arduino Mega2560 or the other compatible board and it can avoid the trouble of connecting cable. With an infrared remote controller(with a CR2025 lithium battery). Feature: Can be controlled by infrared remote(38KHz); Standardized shape design for arduino shield; Driven by 5V / 3.3V normally closed contacts open normally closed contact closed; Working status indicators for each relay; 4 x M3 screw mounting holes easy to install; Note: Remove The plastic sheet before you use the infrared remote controller