The module uses authentic quality relay, normally open interfaces, Maximum load: AC 250V or 10A, DC 30V or 10A Use SMD isolation optocoupler, ability to drive, stable performance.Trip 5mA current. The operating voltage of the module 5V The module can be high or low by a trigger of the jumper setting. The fault-tolerant design, even if the line is case sensitive, the relay 't work The power indicator (green), the flag of the State of the relay (red) Interface module: 1. DC: positive supply (VCC) 2. DC: power negative (GND) 3. IN: control relay may be high or low level Relay outputs: 1. NO: normally open relay interface 2. COM: Common interface relays 3. NC: normally closed relay interface High and low level triggering options: It is low level trigger when the jumper connects to bottom pin It is high level trigger when the jumper connects a high pin Package contents: 1 x 1-channel level Relay module optocoupler shutter button Four hole mounting bolts, 3.1mm diameter size:50mm x 26mm x 18.5mm (L x W x H) Material:PCB colour:Blue Package Contents: 1 x Relay Module Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 1-3cm.