DIYmall ESP8266 ESP-01 WiFi Serial Transceiver Module with 1MB Flash(pack of 2pcs) The PCB layout has changed for an improvement in WiFi radio performance 1MB Flash Memory Latest version esp-01s,with stronger signal Document link: https://nurdspace.nl/ESP8266, video link video link:https://youtu.be/mS2kQVD5Sxw What You Get: 2 X ESP8266-01 Module. Our 1 Year Warranty and Friendly Customer Service.