Adopt new (non-pre-used) CH340 original chip The USB interface is more secure Complete documentation Every piece of shipping board is rigorously tested (testing a board takes 2-5 minutes), strictly controlling quality NodeMCU has ESP-12 based serial WiFi integrated on board to provide GPIO, PWM, ADC, I2C and 1-WIRE resources at your finger tips built-in USB-TTL serial with super reliable industrial strength CH340 for superior stability on all supported platforms ESP8266 is a highly integrated chip designed for the needs of a new connected world. It offers a complete and self-contained Wi-Fi networking solution, allowing it to either host the application or to offload all Wi-Fi networking functions from another application processor. ESP8266 has powerful on-board processing and storage capabilities that allow it to be integrated with the sensors and other application specific devices through its GPIOs with minimal development up-front and minimal loading during run-time. Its high degree of on-chip integration allows for minimal external circuitry, and the entire solution, including front-end module, is designed to occupy minimal PCB area. Package Including: 4 x ESP8266 development board