1、This board is designed with square type-b USB interface, stable connection. 2、It uses imported high-performance USB control chip. 3、High quality relay and dedicated relay driven ULN2803 chip ensure relay to work more stably. 4、There are two flexible and convenient power input methods, power socket and terminal. 5、After connecting the power supply, relay can maintain the setting state even if the computer is power off or USB is disconnected from computer. Note: Please check first and make sure you know how to use it, because we can not provide any technical support. Features: This board is designed with square type-b USB interface, stable connection. It uses imported high-performance USB control chip. High quality relay and dedicated relay driven ULN2803 chip ensure relay to work more stably. There are two flexible and convenient power input methods, power socket and terminal. After connecting the power supply, relay can maintain the setting state even if the computer is power off or USB is disconnected from computer. It supports for WIN 7, XP, 32 bit, 64 bit system, convenient and easy to use. Application: smart switch control for home, hotel, electric appliance, greenhouses, market, company, factory, and time control for Internet cafe, karaoke, IOT, industrial control equipment, test equipment power supply, street lamp, smart management, centralized power management, etc. Specification: Input Current: >300mA Wiring Method: NC/COM/NO Weight: 112g / 4oz (approx.) Package list: 1 *  Smart Controller