The USB relay module is equipped with a stable USB to serial port chip and microcontroller. The serial port debugging software can be used on the computer to send serial port commands to control the opening and closing of 4 relays. Onboard 8-bit high-performance microcontroller chip, onboard CH340 USB to serial port control chip. Onboard power LED indicator and relay status LED indicator. Onboard 4-way 5V, 10A/250VAC, 10A/30VDC relays, the relay life is long and can be continuously attracted 100,000 times. Power supply voltage: 5V, supports USB power supply/external power supply switching Output type: relay switch signal The module has overcurrent protection and relay diode freewheeling protection functions. Color: Green Material: PCB+Components There are differences in printing due to different batches, which not affect the use; there are color differences due to different lighting or displays Package Contents: 1 x USB Relay Module Only the above package content, other products are not included. Note: Light reflection 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.