his module is a USB adapter or programmer for ESP01S that based on ESP8266 WiFi microcontroller. This adapter uses CP2104 USB serial port chip and adds ESP01 automatic download circuit. It is very convenient for users to download program into ESP-01/01S, upgrade firmware, serial debugging and so on. It supports software download from application like Arduino IDE and ESP8266 Flasher with just clicking one button. There is no need to press any button on the adapter or ESP01. The WiFi module will automatically enter the download mode.