Description: The control area of the module has a separation slot from the load area Using double-sided FR-4 circuit board design, high-end chip production process With power and relay action instructions, pull the light, disconnect is not bright When the signal input has a low level signal, the common terminal and the normally open terminal are turned on The relay can directly control various devices and loads There is a normally open and a normally closed contact Blue KF301 terminal access control line more convenient Specification: Material: PCB Board Color: As picture show Size(LxWxH): Approx. 43x17x18.5mm/1.70x0.67x0.73inch Package Includes: 1 piece Relay Module Board(5 Pack) Note: Power should be DC, the voltage should be consistent with the voltage of the relay. Due to the difference in the measurement , pls allow an error of 1 to 3mm.