Feature: 1. VOLTAGE RANGE: 1 channel relay module, using DC 7‑24V power supply, optocoupler input signal range is DC 3.3‑24V, with a wide range of applications. 2. MODULE INTERFACE: The relay module has RS232 TTL UART communication interface, supports power down save, stable connection and simple operation. 3. GOOD PROTECTION: With diode electric leakage protection, 100000 times of continuous suction, the control switch relay module has a long service life. 4. EXCELLENT MATERIAL: Using excellent PCB and electronic components, this 1 channel relay module board has stable performance and less interference. 5. COMPACT SIZE: The control switch relay module has a compact size, easy to install and takes up little space, which is convenient and practical. Specification: Item Type: 1 Channel Relay Module Material: PCB Power Supply Voltage: DC 7-24V Optocoupler Input Signal Range: DC 3.3-24V Communication Baud Rate: 4800, 9600, 19200, default 9600bps, support power down save Communication Interface: RS232 TTL UART interface Device Address: Range 1-255, default 255, support power down save. Package List: 1 x Relay Module