Relay Shield v1.0 5V 4-Channel Relay Module for Arduino (Works with official Arduino Boards)
Relay Shield is a small current signal control module can achieve singlechip to control large power device; Widely use in singlechip home device; Can be plug to the main board which is compatible with Arduino; 4-channel relay stand Arduino Shield interface; 3-M3 screw hole easy to install; Driven by 5V / 3.3V normally open contact close; With red LED indicator onboard; Note: Please avoid the green terminal short-circuit by the housing as connecting with Arduino UNO main board