Description: 5V 2 Channel SPDT relay output modules. With optocoupler. A common end, a normally open end, and a normally closed end. Optocoupler isolation, good anti-interference. Low level , high level release. The status indicator is on when the pump is closed, and the status indicator is off when it is released. There are 4 fixing screw holes around the board, the hole diameter is 3.1mm, which is convenient for installation and fixing. VCC is the system power supply and JD_VCC is the relay power supply. Specification: Supply voltage: 5V DC Current: 100mA Load: 250V 10A AC / 30V 10A DC Size: 50.5x 38.5x 18.5mm/1.99x 1.51x 0.73 inch Wiring instructions: VCC: System power supply positive GND: System power supply negative IN1--IN2: Relay Control Port Package Includes: 1 Piece 5V 2 channel relay module Note: The above size is measured by hand, please allow slightly difference. Thanks !