It is a 5V 1 Channel Without Light Coupling Relay. The relay normally open interface maximum load: AC 250V/10A, DC 30V/10A. It has a trigger current of 5mA, and module working voltage of DC 5V. Each channel of the module can be triggered by a jumper to set a high level or a low level. Fault-tolerant design, even if the control line is disconnected, the relay will not move. With status indicator: power (green), 1-channel relay status indicator (red). All module size interfaces can be directly connected through the terminal block, which is convenient and practical.